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  • C++ Exam Question

    - by Carlucho
    I just took an exam where i was asked the following: Write the function body of each of the methods GenStrLen, InsertChar and StrReverse for the given code bellow. You must take into consideration the following; How strings are constructed in C++ The string must not overflow Insertion of character increases its length by 1 An empty string is indicated by StrLen = 0 class Strings { private: char str[80]; int StrLen; public: // Constructor Strings() { StrLen=0; }; // A function for returning the length of the string 'str' int GetStrLen(void) { }; // A function to inser a character 'ch' at the end of the string 'str' void InsertChar(char ch) { }; // A function to reverse the content of the string 'str' void StrReverse(void) { }; }; The answer I gave was something like this (see bellow). My one of problem is that used many extra variables and that makes me believe am not doing it the best possible way, and the other thing is that is not working.... class Strings { private: char str[80]; int StrLen; int index; // *** Had to add this *** public: Strings(){ StrLen=0; } int GetStrLen(void){ for (int i=0 ; str[i]!='\0' ; i++) index++; return index; // *** Here am getting a weird value, something like 1829584505306 *** } void InsertChar(char ch){ str[index] = ch; // *** Not sure if this is correct cuz I was not given int index *** } void StrRevrse(void){ GetStrLen(); char revStr[index+1]; for (int i=0 ; str[i]!='\0' ; i++){ for (int r=index ; r>0 ; r--) revStr[r] = str[i]; } } }; I would appreciate if anyone could explain me toughly what is the best way to have answered the question and why. Also how come my professor closes each class function like " }; " i thought that was only used for ending classes and constructors only. Thanks a lot for your help.

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  • Building a DataTable in C# with one column at a time

    - by Awaken
    I am trying to build a Retirement Calculator as a chance to make something useful and learn C# better. Currently, I am trying to build a DataTable with a dynamic amount of rows/columns. For context, I ask the user for some inputs regarding salary, % of salary being invested, and expected ROI. I have some other stuff too, but it isn't really part of the issue I am having. Because the number of columns I need for the DataTable is unknown until the formula is run (while+for loop completes), I am having trouble doing things as DataColumns. Hopefully the code below will help. I am really trying to build the table one column at a time. I realize I could reverse it to build it one row at a time because the Years before retirement (yearsRetire) is known, but I would prefer not to and I want to learn more. Sorry for the indentation and commenting. I tried to leave some of my commented coding attempts in there. Thanks for any help. public double calcROI() { double testROI = 0.00; double tempRetireAmount = 0; double adjustRetire = goalAmount * (1 + (Math.Pow(inflation,yearsRetire))); // Loop through ROI values until the calculated retire amount with the test ROI // is greater than the target amount adjusted for inflation while (tempRetireAmount < adjustRetire) { //Increment ROI by 1% per while iteration testROI += .01; //Make a new Column to hold the values for ROI for this while iteration //dtMain.Columns.Add(Convert.ToString(testROI)); //DataColumn tempdc = new DataColumn(Convert.ToString(testROI)); //Loop through the number of years entered by user and see the amount //at Retirement with current ROI for (int i = 0; i < yearsRetire; i++) { //Main formula to calculate amount after i years tempRetireAmount = (tempRetireAmount + salary*savingsPct) * (1 + testROI); // Add value for this year/ROI to table/column //DataRow dr = .NewRow(); //dr tempRetireAmount; //tempdc[i] = tempRetireAmount; } //Need to add column of data to my Main DataTable //dtMain.Rows.Add(dr); //dtMain.Columns.Add(tempdc); } return testROI; }

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  • .Net Custom Components "disappear" after file save

    - by EatATaco
    I might have a hard time explaining this because I am at a total loss for what is happening so I am just looking for some guidance. I might be a bit wordy because I don't know exactly what is the relevant information. I am developing a GUI for a project that I am working on in using .Net (C#) Part of the interface mimics, exactly, what we do in another product. For consistency reasons, my boss wants me to make it look the same way. So I got the other software and basically copied and pasted the components into my new GUI. This required me to introduce a component library (the now defunct Graphics Server GSNet, so I can't go to them for help) so I could implement some simple graphs and temperature/pressure "widgets." The components show up fine, and when I compile, everything seems to work fine. However, at some point during my programming it just breaks. Sometimes the tab that these components are on starts throwing exceptions when I view the designer page (A missing method exception) so it won't display. Sometimes JUST those components from the GSNet library don't show up. Sometimes, if I try to run it, I get a not-instantiated exception on one of their lines of code in the designer code file. Sometimes I can't view the designer at all. No matter what I do I can't reverse it. Even if I undo what I just did it won't fix it. If it happens, I have to revert to a backup and start over again. So I started to backup pretty much every step. I compile it and it works. I comment out a line of code, save it, and then uncomment that same line of code (so I am working with the same exact code) and the components all disappear. It doesn't matter what line of code I actually comment out, as long as it is in the same project that these components are being used. I pretty much have to use the components. . . so does anyone have any suggestion or where I can look to debug this?

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  • C++ exam question on string class implementation

    - by Carlucho
    I just took an exam where i was asked the following: Write the function body of each of the methods GenStrLen, InsertChar and StrReverse for the given code bellow. You must take into consideration the following; How strings are constructed in C++ The string must not overflow Insertion of character increases its length by 1 An empty string is indicated by StrLen = 0 class Strings { private: char str[80]; int StrLen; public: // Constructor Strings() { StrLen=0; }; // A function for returning the length of the string 'str' int GetStrLen(void) { }; // A function to inser a character 'ch' at the end of the string 'str' void InsertChar(char ch) { }; // A function to reverse the content of the string 'str' void StrReverse(void) { }; }; The answer I gave was something like this (see bellow). My one of problem is that used many extra variables and that makes me believe am not doing it the best possible way, and the other thing is that is not working.... class Strings { private: char str[80]; int StrLen; int index; // *** Had to add this *** public: Strings(){ StrLen=0; } int GetStrLen(void){ for (int i=0 ; str[i]!='\0' ; i++) index++; return index; // *** Here am getting a weird value, something like 1829584505306 *** } void InsertChar(char ch){ str[index] = ch; // *** Not sure if this is correct cuz I was not given int index *** } void StrRevrse(void){ GetStrLen(); char revStr[index+1]; for (int i=0 ; str[i]!='\0' ; i++){ for (int r=index ; r>0 ; r--) revStr[r] = str[i]; } } }; I would appreciate if anyone could explain me toughly what is the best way to have answered the question and why. Also how come my professor closes each class function like " }; " i thought that was only used for ending classes and constructors only. Thanks a lot for your help.

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  • True / false evaluation doesn't work as expected in Scheme

    - by ron
    I'm trying to compare two booleans : (if (equal? #f (string->number "123b")) "not a number" "indeed a number") When I run this in the command line of DrRacket I get "not a number" , however , when I put that piece of code in my larger code , the function doesn't return that string ("not a number") , here's the code : (define (testing x y z) (define badInput "ERROR") (if (equal? #f (string->number "123b")) "not a number" "indeed a number") (display x)) And from command line : (testing "123" 1 2) displays : 123 Why ? Furthermore , how can I return a value , whenever I choose ? Here is my "real" problem : I want to do some input check to the input of the user , but the thing is , that I want to return the error message if I need , before the code is executed , because if won't - then I would run the algorithm of my code for some incorrect input : (define (convert originalNumber s_oldBase s_newBase) (define badInput "ERROR") ; Input check - if one of the inputs is not a number then return ERROR (if (equal? #f (string->number originalNumber)) badInput) (if (equal? #f (string->number s_oldBase)) badInput) (if (equal? #f (string->number s_newBase)) badInput) (define oldBase (string->number s_oldBase)) (define newBase (string->number s_newBase)) (define outDecimal (convertIntoDecimal originalNumber oldBase)) (define result "") ; holds the new number (define remainder 0) ; remainder for each iteration (define whole 0) ; the whole number after dividing (define temp 0) (do() ((= outDecimal 0)) ; stop when the decimal value reaches 0 (set! whole (quotient outDecimal newBase)) ; calc the whole number (set! temp (* whole newBase)) (set! remainder (- outDecimal temp)) ; calc the remainder (set! result (appending result remainder)) ; append the result (set! outDecimal (+ whole 0)) ; set outDecimal = whole ) ; end of do (if (> 1 0) (string->number (list->string(reverse (string->list result))))) ) ;end of method This code won't work since it uses another method that I didn't attach to the post (but it's irrelevant to the problem . Please take a look at those three IF-s ... I want to return "ERROR" if the user put some incorrect value , for example (convert "23asb4" "b5" "9") Thanks

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  • How can I maintain a sorted hash in Perl?

    - by srk
    @aoh =( { 3 => 15, 4 => 8, 5 => 9, }, { 3 => 11, 4 => 25, 5 => 6, }, { 3 => 5, 4 => 18, 5 => 5, }, { 0 => 16, 1 => 11, 2 => 7, }, { 0 => 21, 1 => 13, 2 => 31, }, { 0 => 11, 1 => 14, 2 => 31, }, ); I want the hashes in each array index sorted in reverse order based on values.. @sorted = sort { ........... please fill this..........} @aoh; expected output @aoh =( { 4 => 8, 5 => 9, 3 => 15, }, { 5 => 6, 3 => 11, 4 => 25, }, { 5 => 5, 3 => 5, 4 => 18, }, { 2 => 7, 1 => 11, 0 => 16, }, { 1 => 13, 0 => 21, 2 => 31, }, { 0 => 11, 1 => 14, 2 => 31, }, ); Please help.. Thanks in advance.. Stating my request again: I only want the hashes in each array index to be sorted by values.. i dont want the array to be sorted..

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  • Cisco ASA (Client VPN) to LAN - through second VPN to second LAN

    - by user50855
    We have 2 site that is linked by an IPSEC VPN to remote Cisco ASAs: Site 1 1.5Mb T1 Connection Cisco(1) 2841 Site 2 1.5Mb T1 Connection Cisco 2841 In addition: Site 1 has a 2nd WAN 3Mb bonded T1 Connection Cisco 5510 that connects to same LAN as Cisco(1) 2841. Basically, Remote Access (VPN) users connecting through Cisco ASA 5510 needs access to a service at the end of Site 2. This is due to the way the service is sold - Cisco 2841 routers are not under our management and it is setup to allow connection from local LAN VLAN 1 IP address 10.20.0.0/24. My idea is to have all traffic from Remote Users through Cisco ASA destined for Site 2 to go via the VPN between Site 1 and Site 2. The end result being all traffic that hits Site 2 has come via Site 1. I'm struggling to find a great deal of information on how this is setup. So, firstly, can anyone confirm that what I'm trying to achieve is possible? Secondly, can anyone help me to correct the configuration bellow or point me in the direction of an example of such a configuration? Many Thanks. interface Ethernet0/0 nameif outside security-level 0 ip address 7.7.7.19 255.255.255.240 interface Ethernet0/1 nameif inside security-level 100 ip address 10.20.0.249 255.255.255.0 object-group network group-inside-vpnclient description All inside networks accessible to vpn clients network-object 10.20.0.0 255.255.255.0 network-object 10.20.1.0 255.255.255.0 object-group network group-adp-network description ADP IP Address or network accessible to vpn clients network-object 207.207.207.173 255.255.255.255 access-list outside_access_in extended permit icmp any any echo-reply access-list outside_access_in extended permit icmp any any source-quench access-list outside_access_in extended permit icmp any any unreachable access-list outside_access_in extended permit icmp any any time-exceeded access-list outside_access_in extended permit tcp any host 7.7.7.20 eq smtp access-list outside_access_in extended permit tcp any host 7.7.7.20 eq https access-list outside_access_in extended permit tcp any host 7.7.7.20 eq pop3 access-list outside_access_in extended permit tcp any host 7.7.7.20 eq www access-list outside_access_in extended permit tcp any host 7.7.7.21 eq www access-list outside_access_in extended permit tcp any host 7.7.7.21 eq https access-list outside_access_in extended permit tcp any host 7.7.7.21 eq 5721 access-list acl-vpnclient extended permit ip object-group group-inside-vpnclient any access-list acl-vpnclient extended permit ip object-group group-inside-vpnclient object-group group-adp-network access-list acl-vpnclient extended permit ip object-group group-adp-network object-group group-inside-vpnclient access-list PinesFLVPNTunnel_splitTunnelAcl standard permit 10.20.0.0 255.255.255.0 access-list inside_nat0_outbound_1 extended permit ip 10.20.0.0 255.255.255.0 10.20.1.0 255.255.255.0 access-list inside_nat0_outbound_1 extended permit ip 10.20.0.0 255.255.255.0 host 207.207.207.173 access-list inside_nat0_outbound_1 extended permit ip 10.20.1.0 255.255.255.0 host 207.207.207.173 ip local pool VPNPool 10.20.1.100-10.20.1.200 mask 255.255.255.0 route outside 0.0.0.0 0.0.0.0 7.7.7.17 1 route inside 207.207.207.173 255.255.255.255 10.20.0.3 1 crypto ipsec transform-set ESP-3DES-SHA esp-3des esp-sha-hmac crypto ipsec security-association lifetime seconds 28800 crypto ipsec security-association lifetime kilobytes 4608000 crypto dynamic-map outside_dyn_map 20 set transform-set ESP-3DES-SHA crypto dynamic-map outside_dyn_map 20 set security-association lifetime seconds 288000 crypto dynamic-map outside_dyn_map 20 set security-association lifetime kilobytes 4608000 crypto dynamic-map outside_dyn_map 20 set reverse-route crypto map outside_map 20 ipsec-isakmp dynamic outside_dyn_map crypto map outside_map interface outside crypto map outside_dyn_map 20 match address acl-vpnclient crypto map outside_dyn_map 20 set security-association lifetime seconds 28800 crypto map outside_dyn_map 20 set security-association lifetime kilobytes 4608000 crypto isakmp identity address crypto isakmp enable outside crypto isakmp policy 20 authentication pre-share encryption 3des hash sha group 2 lifetime 86400 group-policy YeahRightflVPNTunnel internal group-policy YeahRightflVPNTunnel attributes wins-server value 10.20.0.9 dns-server value 10.20.0.9 vpn-tunnel-protocol IPSec password-storage disable pfs disable split-tunnel-policy tunnelspecified split-tunnel-network-list value acl-vpnclient default-domain value YeahRight.com group-policy YeahRightFLVPNTunnel internal group-policy YeahRightFLVPNTunnel attributes wins-server value 10.20.0.9 dns-server value 10.20.0.9 10.20.0.7 vpn-tunnel-protocol IPSec split-tunnel-policy tunnelspecified split-tunnel-network-list value YeahRightFLVPNTunnel_splitTunnelAcl default-domain value yeahright.com tunnel-group YeahRightFLVPN type remote-access tunnel-group YeahRightFLVPN general-attributes address-pool VPNPool tunnel-group YeahRightFLVPNTunnel type remote-access tunnel-group YeahRightFLVPNTunnel general-attributes address-pool VPNPool authentication-server-group WinRadius default-group-policy YeahRightFLVPNTunnel tunnel-group YeahRightFLVPNTunnel ipsec-attributes pre-shared-key *

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  • Building nginx 1.0.4 on Amazon EC2 micro - perl and python problems

    - by digitaltoast
    I'd like to run nginx as a reverse proxy with apache2 on my EC2 micro instance. yum install nginx gives me nginx-0.8.53-1.2.amzn1.x86_64.rpm The current nginx is 1.0.4 I found and followed this guide: http://kdn2.info/2011/05/install-nginx-on-amazon-ec2/ It works fine up to and including "make". When I get to checkinstall --fstrans=no I get ERROR: ld.so: object '/usr/lib/installwatch.so' from LD_PRELOAD cannot be preloaded: ignored. test -d '/var/log/nginx' || mkdir -p '/var/log/nginx' ERROR: ld.so: object '/usr/lib/installwatch.so' from LD_PRELOAD cannot be preloaded: ignored. make[1]: Leaving directory `/root/src/nginx-1.0.4' ======================== Installation successful ========================== Copying documentation directory... ./ ./CHANGES ./LICENSE ./README cp: cannot stat `//var/tmp/gRWoVgIcdbmjfTjoVGBM/newfiles.tmp': No such file or directory Copying files to the temporary directory...OK Striping ELF binaries and libraries...OK Compressing man pages...OK Building file list...OK Building RPM package... FAILED! *** Failed to build the package ...and the logfile is full of: Building target platforms: x86_64 Building for target x86_64 Processing files: nginx-1.0.4-1.x86_64 error: File not found: /usr/src/rpm/BUILDROOT/nginx-1.0.4-1.x86_64/usr error: File not found: /usr/src/rpm/BUILDROOT/nginx-1.0.4-1.x86_64/usr/doc There IS /usr/src/rpm/BUILDROOT/nginx-1.0.4-1.x86_64/ but no /usr Following further down the page, it says: "If we want to use, for example, PHP 5.2 we can download PHP and Nginx compatible with Amazon Kernel(Xen Kernel) from the CentosALT Repository." So I install the two repositories, but when I yum install http://centos.alt.ru/pub/nginx/1.0/RPMS/x86_64/nginx-stable-1.0.4-1.el5.x86_64.rpm I get Error: Package: nginx-stable-1.0.4-1.el5.x86_64 (/nginx-stable-1.0.4-1.el5.x86_64) Requires: perl(:MODULE_COMPAT_5.8.8) You could try using --skip-broken to work around the problem but that doesn't fix it. When I do yum update, I get --> Finished Dependency Resolution Error: Package: python-distribute-0.6.19-10.1.x86_64 (devel_languages_python) Requires: python < 2.5 Installed: 1:python-2.6-1.19.amzn1.noarch (@amzn-main) python = 1:2.6-1.19.amzn1 Error: Package: python-distribute-0.6.19-10.1.i586 (devel_languages_python) Requires: python < 2.5 Installed: 1:python-2.6-1.19.amzn1.noarch (@amzn-main) python = 1:2.6-1.19.amzn1 I've tried everything - yum clean all and various other suggestions found on other sites. If anyone has any suggestions or a known package of the current 1.04 nginx working on EC2 Micro (Linux ip-10-56-63-85 2.6.35.11-83.9.amzn1.x86_64 #1 SMP Sat Feb 19 23:42:04 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux - which I think is RHEL 5?) then I'd be grateful. Incidentally, does this repolist look right? repo id repo name status CentALT CentALT Packages for Enterprise Linux 5 - x86_64 enabled: 112+157 amzn-main amzn-main-Base enabled: 2,706 amzn-main-debuginfo amzn-main-debuginfo disabled amzn-main-nosrc amzn-main-nosrc disabled amzn-updates amzn-updates-Base enabled: 328 amzn-updates-debuginfo amzn-updates-debuginfo disabled amzn-updates-nosrc amzn-updates-nosrc disabled devel_languages_python Python and Python Modules (SLE_10) enabled: 1,452+768 epel Extra Packages for Enterprise Linux 5 - x86_64 enabled: 5,892+604 epel-debuginfo Extra Packages for Enterprise Linux 5 - x86_64 - Debug disabled epel-source Extra Packages for Enterprise Linux 5 - x86_64 - Source disabled epel-testing Extra Packages for Enterprise Linux 5 - Testing - x86_64 disabled epel-testing-debuginfo Extra Packages for Enterprise Linux 5 - Testing - x86_64 - Debug disabled epel-testing-source Extra Packages for Enterprise Linux 5 - Testing - x86_64 - Source disabled s3tools Tools for managing Amazon S3 - Simple Storage Service (RHEL_6) enabled: 2+1 repolist: 10,492

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  • Ubuntu server random hangups.

    - by Ebbe
    Hello all. this is my first post to this forum which I found through the superb podcast "It Conversations" from StackOverFlow. I am quite in my role as server administrator for an exhibition center in London. Basically we have a central file and sql server to which roughly 40 stations connects to to upload/download data used/captured by a set of applications. Over the last weeks we have experienced a few random hangups to our applications, and as it always happen to multiple applications simultaneously I do not believe that the applications are the source of the problem. We also monitor the network using Dartware Intermapper which indicates that all switches and stations on the network has been reachable during the downtime. Thus, its all pointing to the server. I have been looking through all log files I can think of and the only thing so far that I have found suspicious is the following lines in the syslog which are from the time of one of the hangups: Feb 6 17:14:27 es named[5582]: client 127.0.0.1#33721: RFC 1918 response from Internet for 150.0.168.192.in-addr.arpa Feb 6 17:14:40 es named[5582]: client 127.0.0.1#32899: RFC 1918 response from Internet for 152.0.168.192.in-addr.arpa Feb 6 17:15:01 es /USR/SBIN/CRON[1956]: (es) CMD (/home/es/apps/es/bin/es_checksum.sh) Feb 6 17:16:06 es /USR/SBIN/CRON[2031]: (es) CMD (/home/es/apps/es/bin/es_checksum.sh) Feb 6 17:21:00 es named[5582]: *** POKED TIMER *** Feb 6 17:21:00 es last message repeated 2 times Feb 6 17:21:07 es named[5582]: client 127.0.0.1#44194: RFC 1918 response from Internet for 143.0.168.192.in-addr.arpa Feb 6 17:21:12 es named[5582]: client 127.0.0.1#59004: RFC 1918 response from Internet for 164.0.168.192.in-addr.arpa I find a few lines of interesting lines here: 1) "RFC 1918 response from Internet for 150.1.168.192.in-addr.arpa". I see this a lot in the syslog. And basically everytime I do a nslookup for any of the computers in the cluster I get a new similar line in the syslog. I understand from google that this has to do with reverse lookup problems. But I do not know how that could effect the systems. Lets say that one of these lines appear every time one of the userstations connects to the server, which may happen several times a second. Could this possible cause a hangup of the entire server? 2) POKED TIMER, I have googled this quite a lot, but not found an explaination that I can relate to. What does this mean? 3) The timestamps, it seems like the entire server has stopped responding for several minutes. Normally there are many printouts to the syslog per minute on this server. Furthermore the CRON job is set to run once every minute. Which according to the log, hasent happened here. OS: Ubuntu 8.04 Kernel: Linux 2.6.24-24-server x86_64 GNU/Linux. Hardware: Dell R710, RAID1, CPU: 2x XEON E5530. 16GB Memory. Average load is very low, and memory should not be a problem. Please let me know if you need any additional information. Best wishes, Ebbe

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  • apache+mod_wsgi configuration for django project(s) on a quad core

    - by Stefano
    I've been experiment quite some time with a "typical" django setting upon nginx+apache2+mod_wsgi+memcached(+postgresql) (reading the doc and some questions on SO and SF, see comments) Since I'm still unsatisfied with the behavior (definitely because of some bad misconfiguration on my part) I would like to know what a good configuration would look like with these hypotesis: Quad-Core Xeon 2.8GHz 8 gigs memory several django projects (anything special related to this?) These are excerpts form my current confs: apache2 SetEnv VHOST null #WSGIPythonOptimize 2 <VirtualHost *:8082> ServerName subdomain.domain.com ServerAlias www.domain.com SetEnv VHOST subdomain.domain AddDefaultCharset UTF-8 ServerSignature Off LogFormat "%{X-Real-IP}i %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-agent}i\"" custom ErrorLog /home/project1/var/logs/apache_error.log CustomLog /home/project1/var/logs/apache_access.log custom AllowEncodedSlashes On WSGIDaemonProcess subdomain.domain user=www-data group=www-data threads=25 WSGIScriptAlias / /home/project1/project/wsgi.py WSGIProcessGroup %{ENV:VHOST} </VirtualHost> wsgi.py import os import sys # setting all the right paths.... _realpath = os.path.realpath(os.path.dirname(__file__)) _public_html = os.path.normpath(os.path.join(_realpath, '../')) sys.path.append(_realpath) sys.path.append(os.path.normpath(os.path.join(_realpath, 'apps'))) sys.path.append(os.path.normpath(_public_html)) sys.path.append(os.path.normpath(os.path.join(_public_html, 'libs'))) sys.path.append(os.path.normpath(os.path.join(_public_html, 'django'))) os.environ['DJANGO_SETTINGS_MODULE'] = 'settings' import django.core.handlers.wsgi _application = django.core.handlers.wsgi.WSGIHandler() def application(environ, start_response): """ Launches django passing over some environment (domain name) settings """ application_group = environ['mod_wsgi.application_group'] """ wsgi application group is required. It's also used to generate the HOST.DOMAIN.TLD:PORT parameters to pass over """ assert application_group fields = application_group.replace('|', '').split(':') server_name = fields[0] os.environ['WSGI_APPLICATION_GROUP'] = application_group os.environ['WSGI_SERVER_NAME'] = server_name if len(fields) > 1 : os.environ['WSGI_PORT'] = fields[1] splitted = server_name.rsplit('.', 2) assert splitted >= 2 splited.reverse() if len(splitted) > 0 : os.environ['WSGI_TLD'] = splitted[0] if len(splitted) > 1 : os.environ['WSGI_DOMAIN'] = splitted[1] if len(splitted) > 2 : os.environ['WSGI_HOST'] = splitted[2] return _application(environ, start_response)` folder structure in case it matters (slightly shortened actually) /home/www-data/projectN/var/logs /project (contains manage.py, wsgi.py, settings.py) /project/apps (all the project ups are here) /django /libs Please forgive me in advance if I overlooked something obvious. My main question is about the apache2 wsgi settings. Are those fine? Is 25 threads an /ok/ number with a quad core for one only django project? Is it still ok with several django projects on different virtual hosts? Should I specify 'process'? Any other directive which I should add? Is there anything really bad in the wsgi.py file? I've been reading about potential issues with the standard wsgi.py file, should I switch to that? Or.. should this conf just be running fine, and I should look for issues somewhere else? So, what do I mean by "unsatisfied": well, I often get quite high CPU WAIT; but what is worse, is that relatively often apache2 gets stuck. It just does not answer anymore, and has to be restarted. I have setup a monit to take care of that, but it ain't a real solution. I have been wondering if it's an issue with the database access (postgresql) under heavy load, but even if it was, why would the apache2 processes get stuck? Beside these two issues, performance is overall great. I even tried New Relic and got very good average results.

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  • Why do GPUs overheat?

    - by JAD
    About a year ago, I added a 9800GT (1 GB version) and a Corsair CX500 PSU to an HP M8000N computer. A few weeks ago, the HDD overheated and I decided to transfer the GPU & PSU to a new build, which consists of: i3 @ 3.3Ghz Gigabyte H61 Micro ATX Mobo 4GB RAM 500GB WD HDD DVD RW Drive Cooler Master Elite 430 Tower Once I had Win7 up and running, I installed all the essential drivers that came with the Gigabyte Mobo CD. However, whenever I tried installing the Graphics Media Accelerator driver, the computer would crash and enter an endless boot sequence on the next startup. I skipped installing this driver and installed the CD driver for the 9800GT, which by now is a year old. Everything was working fine, WEI rated my GPU at 6.6 graphics & aero performance. However, after updating my Nvidia drivers to the latest, the WEI dropped my rating to 3.3 for Aero, and 4.7 for graphics performance. Just to make sure that everything was ok, I ran Bad Company 2 on medium settings. The first few minutes ran just fine at a smooth framerate, so I dismissed this as Windows being Windows. About 6 hours later, I ran BC2 again. This time I averaged anywhere from 2-5 FPS. I checked the GPU temperature through GPU-Z, and it came back as 120C. The problem with this, is that the computer was on for six hours up to that point. Wouldn't the card have experienced a reactor core meltdown a lot sooner than that? Granted, the computer was "sleeping" some of the time, but still... The next day I took out a temperature gun and ran some tests. I would point the laser at a very specific area on the reverse side of the card (not the fan or "front"), and compare the temp reading with GPU-Z. After leaving the system on idle on idle for a few minutes, I ran BC2 twice. Here are the results: GPU-Z Reading / Temp Gun Reading / Time Null / 22.3°C / Comp is Off 53°C / 33.5°C / 1:49 78°C / 46°C / 1:53 - (First BC2 run; good framerate) 102°C / 64.6°C / 2:01 - (System is again on idle) 113°C / 64.8°C / 2:10 119°C / 71.8°C / 2:17 - (Second BC2 run; poor framerate) I should also mention that I also took a temp recording of another part of the GPU from 2:01-2:17. The temp in this area jumped from 75°C to 82.9°C in that time frame. This pretty much confirms that GPU-Z is reporting the temperature accurately, and the card is overheating. But I'd like to know why; the cars is doing nothing and still the temperature climbs at a steady rate. I thoroughly cleaned the GPU and PSU when I salvaged them from the old HP M8000N computer with a can of compressed air, dust cant be the issue. Similarly, the rest of the computer is brand new. I installed various Nvidia drivers, but no luck. It seems strange to me that a year-old card is suddenly failing on me; aren't they supposed to last at least two years? Could this be a driver issue? Is the motherboard faulty? Could the PSU be overfeeding the card on voltage? Neither case seems likely, as the CPU, RAM and otherwise the rest of the comp has worked flawlessly and has stayed well within respectable temp ranges (the i3 lingers around 50C, the HDD stays at 30C, so does the PSU). How can I pinpoint the issue?

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  • Diagnosing packet loss / high latency in Ubuntu

    - by Sam Gammon
    We have a Linux box (Ubuntu 12.04) running Nginx (1.5.2), which acts as a reverse proxy/load balancer to some Tornado and Apache hosts. The upstream servers are physically and logically close (same DC, sometimes same-rack) and show sub-millisecond latency between them: PING appserver (10.xx.xx.112) 56(84) bytes of data. 64 bytes from appserver (10.xx.xx.112): icmp_req=1 ttl=64 time=0.180 ms 64 bytes from appserver (10.xx.xx.112): icmp_req=2 ttl=64 time=0.165 ms 64 bytes from appserver (10.xx.xx.112): icmp_req=3 ttl=64 time=0.153 ms We receive a sustained load of about 500 requests per second, and are currently seeing regular packet loss / latency spikes from the Internet, even from basic pings: sam@AM-KEEN ~> ping -c 1000 loadbalancer PING 50.xx.xx.16 (50.xx.xx.16): 56 data bytes 64 bytes from loadbalancer: icmp_seq=0 ttl=56 time=11.624 ms 64 bytes from loadbalancer: icmp_seq=1 ttl=56 time=10.494 ms ... many packets later ... Request timeout for icmp_seq 2 64 bytes from loadbalancer: icmp_seq=2 ttl=56 time=1536.516 ms 64 bytes from loadbalancer: icmp_seq=3 ttl=56 time=536.907 ms 64 bytes from loadbalancer: icmp_seq=4 ttl=56 time=9.389 ms ... many packets later ... Request timeout for icmp_seq 919 64 bytes from loadbalancer: icmp_seq=918 ttl=56 time=2932.571 ms 64 bytes from loadbalancer: icmp_seq=919 ttl=56 time=1932.174 ms 64 bytes from loadbalancer: icmp_seq=920 ttl=56 time=932.018 ms 64 bytes from loadbalancer: icmp_seq=921 ttl=56 time=6.157 ms --- 50.xx.xx.16 ping statistics --- 1000 packets transmitted, 997 packets received, 0.3% packet loss round-trip min/avg/max/stddev = 5.119/52.712/2932.571/224.629 ms The pattern is always the same: things operate fine for a while (<20ms), then a ping drops completely, then three or four high-latency pings (1000ms), then it settles down again. Traffic comes in through a bonded public interface (we will call it bond0) configured as such: bond0 Link encap:Ethernet HWaddr 00:xx:xx:xx:xx:5d inet addr:50.xx.xx.16 Bcast:50.xx.xx.31 Mask:255.255.255.224 inet6 addr: <ipv6 address> Scope:Global inet6 addr: <ipv6 address> Scope:Link UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1 RX packets:527181270 errors:1 dropped:4 overruns:0 frame:1 TX packets:413335045 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:240016223540 (240.0 GB) TX bytes:104301759647 (104.3 GB) Requests are then submitted via HTTP to upstream servers on the private network (we can call it bond1), which is configured like so: bond1 Link encap:Ethernet HWaddr 00:xx:xx:xx:xx:5c inet addr:10.xx.xx.70 Bcast:10.xx.xx.127 Mask:255.255.255.192 inet6 addr: <ipv6 address> Scope:Link UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1 RX packets:430293342 errors:1 dropped:2 overruns:0 frame:1 TX packets:466983986 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:77714410892 (77.7 GB) TX bytes:227349392334 (227.3 GB) Output of uname -a: Linux <hostname> 3.5.0-42-generic #65~precise1-Ubuntu SMP Wed Oct 2 20:57:18 UTC 2013 x86_64 GNU/Linux We have customized sysctl.conf in an attempt to fix the problem, with no success. Output of /etc/sysctl.conf (with irrelevant configs omitted): # net: core net.core.netdev_max_backlog = 10000 # net: ipv4 stack net.ipv4.tcp_ecn = 2 net.ipv4.tcp_sack = 1 net.ipv4.tcp_fack = 1 net.ipv4.tcp_tw_reuse = 1 net.ipv4.tcp_tw_recycle = 0 net.ipv4.tcp_timestamps = 1 net.ipv4.tcp_window_scaling = 1 net.ipv4.tcp_no_metrics_save = 1 net.ipv4.tcp_max_syn_backlog = 10000 net.ipv4.tcp_congestion_control = cubic net.ipv4.ip_local_port_range = 8000 65535 net.ipv4.tcp_syncookies = 1 net.ipv4.tcp_synack_retries = 2 net.ipv4.tcp_thin_dupack = 1 net.ipv4.tcp_thin_linear_timeouts = 1 net.netfilter.nf_conntrack_max = 99999999 net.netfilter.nf_conntrack_tcp_timeout_established = 300 Output of dmesg -d, with non-ICMP UFW messages suppressed: [508315.349295 < 19.852453>] [UFW BLOCK] IN=bond1 OUT= MAC=<mac addresses> SRC=118.xx.xx.143 DST=50.xx.xx.16 LEN=68 TOS=0x00 PREC=0x00 TTL=51 ID=43221 PROTO=ICMP TYPE=3 CODE=1 [SRC=50.xx.xx.16 DST=118.xx.xx.143 LEN=40 TOS=0x00 PREC=0x00 TTL=249 ID=10220 DF PROTO=TCP SPT=80 DPT=53817 WINDOW=8190 RES=0x00 ACK FIN URGP=0 ] [517787.732242 < 0.443127>] Peer 190.xx.xx.131:59705/80 unexpectedly shrunk window 1155488866:1155489425 (repaired) How can I go about diagnosing the cause of this problem, on a Debian-family Linux box?

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  • Troubleshooting unwanted NTP Traffic

    - by Jaxaeon
    A domain controller running Windows Server 2012 is sending NTP and NETBIOS traffic to an address that has never been configured as a time provider. The server logs give no indication that any NTP traffic is failing. The only place I see any evidence of this traffic is in pfSense system logs: (Blocked) Jun 9 08:48:50 DOMAIN 10.0.1.100:123 192.128.127.254:123 UDP (Blocked) Jun 9 08:48:53 DOMAIN 10.0.1.100:137 192.128.127.254:137 UDP As far as I can tell the NTP service is working normally otherwise: DC2.domain.com[10.0.1.101:123]: ICMP: 0ms delay NTP: -0.0131705s offset from DC1.domain.com RefID: DC1.domain.com [10.0.1.100] Stratum: 3 DC1.domain.com *** PDC ***[10.0.1.100:123]: ICMP: 0ms delay NTP: +0.0000000s offset from DC1.domain.com RefID: clock1.albyny.inoc.net [64.246.132.14] Stratum: 2 The time provider NtpClient is currently receiving valid time data from 1.pool.ntp.org,0×1 (ntp.m|0x0|0.0.0.0:123->204.2.134.163:123). The time provider NtpClient is currently receiving valid time data from 0.pool.ntp.org,0×1 (ntp.m|0x0|0.0.0.0:123->64.246.132.14:123). The time service is now synchronizing the system time with the time source 0.pool.ntp.org,0×1 (ntp.m|0x0|0.0.0.0:123->64.246.132.14:123). I've been inside and out of the NTP configuration and cannot find any reason for this traffic. Reverse DNS points the destination address to nothing.attdns.com. pinging nothing.attdns.com from the domain controller in question leads to a response from loopback (127.0.0.2) which makes my head hurt. Any ideas? EDIT1: It should probably be noted that after a dns flush, nslookup 192.128.127.254 returns nothing.attdns.com. 192.128.127.254 is not present in domain.com DNS records. The attdns.com domain is not present in cached lookups. 127.in-addr.arpa is clean of any funkyness. EDIT2: The loopback ping response from nothing.attdns.com is possibly unrelated. Machines on other networks are also displaying this behavior. EDIT3: As mentioned in the comments, I tracked the problem network adapter back to my pfSense VM hosted in esxi 5.5 (I know shame on me for virtualizing a firewall). pfSense was configured to use DC1.domain.com as its primary time provider, but upon changing it back to pool.ntp.org the problem persists. pfSense logs give no indication of NTP misconfiguration. Everywhere I can think to look this VM is identified as 10.0.1.253, so I still have no idea why it’s sending NTP requests as 192.128… Since this firewall was a temporary solution to a problem that no longer exists so I am going to decommission it. EDIT4: The queries were coming from another machine sharing the same virtual adapter as the firewall. The machine has two local adapters: one for LAN, and the other for attached hardware that uses an Ethernet connection. That hardware sits in the the mystery subnet, and the machine is broadcasting NTP requests over both adapters.

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  • Strange enduser experience with Liferay, Glassfish and Apache on RedHat

    - by Pete Helgren
    Tried multiple forums to get to the bottom of this. I hope I can get some direction here: Here is the stack I am working with: Red Hat Enterprise Linux Server release 5.6 (Tikanga) Liferay 6.0.6 on Glassfish 3.0.1 MySQL 5.0.77 Apache 2.2.3 The Liferay portal provides a variety of portlets to end users. Static content (web pages), static resources (primarily pdf and mp3 files 1mb - 80mb in size), File upload and download capabilities (primarily 40-60mb mp3 files) and online streaming of those MP3 files. Here is the strange end user experiences: Under normal load: (20-30) users uploading, downloading or streaming files and 20-30 accessing static content (some of it downloads), we see the following: 1) Clicking a link triggers the download of a portion of an MP3 (the portion is a few seconds long). 2) Clicking on a link tiggers the download of the page content rather than rendering. 3) Clicking a link causes the page to dump binary data to the end user rather than the expected content. 4) Clicking a link returns the text of a javascript file rather than rendering the page. Each occurrence is totally random (or appears so). Sometimes it works, sometimes it doesn't. It seems to have no relation to browser or client OS. The strange events seem to occur much more frequently when using an SSL connection rather than regular http. Apache serves as a proxy server only (reverse). It basically passes all the requests through to Glassfish. There isn't any static content proxy served by Apache. We rebuilt the entire stack from scratch and redeployed the portlet wars and still have the same issues. Liferay is running as a single server (not clustered). We disabled mod_cache in Apache. The problems are more frequent as the server load grows. This morning the load is pretty light and we are seeing few problems but the use of the site will grow, particularly tonight around 9pm CST through Wednesday morning. You could try the site (http://preview.bsfinternational.org) during those times and I would expect that you might experience one of the weirdnesses as you randomly click links on the site (https is invoked only when signed in). Again, https seems to exacerbate the issue. This seems very much like a caching issue but I don't know where in the stack to start peeling the onion. Apache? Liferay? Glassfish? MySQL? Maybe even Redhat? We are stumped and most forums we have posted to (LifeRay and Glassfish) have returned very few suggestions. I just need an idea of where to start looking. I understand that we could have a portlet EDIT: Opening the files in a Hex editor that appear to be pages that download rather than render, we see that the first 4000 characters are "junk" and then the "HTTP/1.1 ...." 'normal' header is seen. So something is dumping a jumble of characters up to offset 4000 (when viewing it in a Hex editor). Perhaps a clue? Ideas?

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  • Multiple data centers and HTTP traffic: DNS Round Robin is the ONLY way to assure instant fail-over?

    - by vmiazzo
    Hi, Multiple A records pointing to the same domain seem to be used almost exclusively to implement DNS Round Robin as a cheap load balancing technique. The usual warning against DNS RR is that it is not good for high availability. When 1 IP goes down clients will continue to use it for minutes. A load balancer is often suggested as a better choice. Both claims are not completely true: When the traffic is HTTP then, most of the HTML browsers are able to automatically try the next A record if the previous is down, without a new DNS look-up. Read here chapter 3.1 and here. When multiple data centers are involved then, DNS RR is the only option to distribute traffic across them. So, is it true that, with multiple data centers and HTTP traffic, the use of DNS RR is the ONLY way to assure instant fail-over when one data center goes down? Thanks, Valentino Edit: Off course each data center has a local Load Balancer with hot spare. It's OK to sacrifice session affinity for an instant fail-over. AFAIK the only way for a DNS to suggest a data center instead of another is to reply with just the IP (or IPs) associated to that data center. If the data center becomes unreachable then all those IP are also unreachables. This means that, even if smart HTML browsers are able to instantly try another A record , all the attempts will fail until the local cache entry expires and a new DNS lookup is done, fetching the new working IPs (I assume DNS automatically suggests to a new data center when one fail). So, "smart DNS" cannot assure instant fail-over. Conversely a DNS round-robin permits it. When one data center fail, the smart HTML browsers (most of them) instantly try the other cached A records jumping to another (working) data center. So, DNS round-robin doesn't assure session affinity or the lowest RTT but seems to be the only way to assure instant fail-over when the clients are "smart" HTML browsers. Edit 2: Some people suggest TCP Anycast as a definitive solution. In this paper (chapter 6) is explained that Anycast fail-over is related to BGP convergence. For this reason Anycast can employ from 15 minutes to 20 seconds to complete. 20 seconds are possible on networks where the topology was optimized for this. Probably just CDN operators can grant such fast fail-overs. Edit 3:* I did some DNS look-ups and traceroutes (maybe some expert can double check) and: The only CDN using TCP Anycast seems to be CacheFly, other operators like CDN networks and BitGravity use CacheFly. Seems that their edges cannot be used as reverse proxies. Therefore, they cannot be used to grant instant failover. Akamai and LimeLight seems to use geo-aware DNS. But! They return multiple A records. From traceroutes seems that the returned IPs are on the same data center. So, I'm puzzled on how they can offer a 100% SLA when one data center goes down.

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  • Bypass DNSSEC for local Stub zones

    - by Starsky
    I am using bind 9.9.2 as a DNSSEC validating recursive resolver in an Internet DMZ. I want to point to my internal DNS servers as stub zones (ideally) or anything except slave zones (to avoid very large zone transfers). We use a routable ip space for our Internal addressing. Sorry if I am using an IP space that you own in my example, but 167.x.x.x is the first zone I found that fits my issue. E.G dnssec-enable yes; dnssec-validation yes; dnssec-accept-expired no; zone "16.172.in-addr.arpa" { type stub; masters { 167.255.1.53; } } zone "myzone.com" in { type stub; masters { 167.255.1.53; } } When queries hit the DNS server, they attempt at being validated, and fail because 167.in-addr.arpa HAS an RRSIG record, but sub zones do not (and should not!). Google dns is used in this example, but in reality it would be my recursive resolver. @8.8.8.8 -x 167.255.1.53 +dnssec ; (1 server found) ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 17488 ;; flags: qr rd ra ad; QUERY: 1, ANSWER: 0, AUTHORITY: 6, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags: do; udp: 512 ;; QUESTION SECTION: ;53.1.255.167.in-addr.arpa. IN PTR ;; AUTHORITY SECTION: 167.in-addr.arpa. 1800 IN SOA z.arin.net. dns-ops.arin.net. 2013100713 1800 900 691200 10800 167.in-addr.arpa. 1800 IN RRSIG SOA 5 3 86400 20131017160124 20131007160124 812 167.in-addr.arpa. Lcl8sCps7LapnAj4n403KXx7A3GO7+2z/9Q2R2mwkh9FL26iDx7GlU4+ NufGd92IEJCdBu9IgcZP4I9QcKi8DI28og27WrfKd5moSl/STj02GliS qPTfNiewmTTIDw5++IlhITbp+CoJuZCRCdDbyWKmd5NSLcbskAwbCVlO vVA= 167.in-addr.arpa. 10800 IN NSEC 1.167.in-addr.arpa. NS SOA TXT RRSIG NSEC DNSKEY 167.in-addr.arpa. 10800 IN RRSIG NSEC 5 3 10800 20131017160124 20131007160124 812 167.in-addr.arpa. XALsd59i+XGvCIzjhTUFXcr11/M8prcaaPQ5yFSbvP9TzqjJ3wpizvH6 202MdrIWbsT1Dndri49lHKAXgBQ5OOsUmOh+eoRYR5okxRO4VLc5Tkze Gh0fQLcwGXPuv9A4SFNIrNyi3XU4Qvq0cViKXIuEGTa3C+zMPuvc0her oKk= 254.167.in-addr.arpa. 10800 IN NSEC 26.167.in-addr.arpa. NS RRSIG NSEC 254.167.in-addr.arpa. 10800 IN RRSIG NSEC 5 4 10800 20131017160124 20131007160124 812 167.in-addr.arpa. xnsLBTnPhdyABdvqtEHPxa6Y6NASfYAWfW1yYlNliTyV8TFeNOqewjwj nY43CWD77ftFDDQTLFEOPpV5vwmnUGYTRztK+kB5UrlflhPgiqYiBaBD RQaFQ8DIKaof8/snusZjK7aNmfe09t9gRcaX/pXn3liKz7m/ggxZi0f9 xo0= ;; Query time: 31 msec ;; SERVER: 8.8.8.8#53(8.8.8.8) ;; WHEN: Mon Oct 7 16:52:59 2013 ;; MSG SIZE rcvd: 722 Is there a way to bypass DNSSEC validation for specific zones? Any zone that I host internally, I do not want DNSSEC validation performed on. I have only see this interfere w/ certain reverse zones where the top level has DS/RRSIG records. Thanks.

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  • Yahoo is sending our server's transactional email to the Spam folder, even though we have set up SPF and DKIM

    - by Derrick Miller
    Yahoo Mail is sending our server's transactional emails to the Spam folder, even though we have taken quite a few anti-spam steps. By contrast, Gmail allows the messages through to the inbox just fine. Here are the things which are in place: SPF is set up for the domain holsteinplaza.com. Yahoo reports spf=pass in the message headers. DKIM is set up for the domain holsteinplaza.com. Yahoo reports dkim=pass in the message headers. We have a proper reverse DNS entry for the sending mail server. Name - IP matches IP - Name. Neither Domainkeys nor SenderID are set up. From what I can tell, DKIM is the way of the future, and there is not much to be gained from adding Domainkeys or SenderID. Following are the headers. Any ideas what more I should do to get Yahoo to stop flagging the emails as spam? From Holstein Plaza Auctions Sat Jun 25 18:30:08 2011 X-Apparently-To: [email protected] via 98.138.90.132; Sat, 25 Jun 2011 18:30:11 -0700 Return-Path: <[email protected]> X-YahooFilteredBulk: 70.32.113.42 Received-SPF: pass (domain of holsteinplaza.com designates 70.32.113.42 as permitted sender) X-YMailISG: i_vaA_QWLDuLOmXhDjUv3aBKJl5Un6EiP6Yk2m4yn3jeEuYK MkhpqIt9zDUbHARCwXrhl9pqjTANurGVca7gytSs.mryWVQcbWBx.DaItWRb VcyrIzwMzXKCSeu06H2a.cJ7HG5vJLJaKmHUUI_1ttXKn_Aegiu5yHvFX83R Lpth0witO9zfaKvOMaJV3LAxpIpFOydwvq1cqjZ8nURxQbxM3Cl.QW7MxxrC 09qLVn_D_xSdU94QdU22IsVmlaRHv.uU5dnIazu.KSkhKpYykDoZA2SH0SY4 JmTZj3LP8N926xXVDzYQ5K6QvKuJL5g0d9pYZx3KC59sgIu5oHlJ3Q15RdKb f3OJw0PR6oIyJ2yStVr8vfbDgOfj3qig03.Tw6g6MMNpv1G7Cuol4oJeUaYP xELxX6dHgBgCSuWMcbsrxbK4BIXcS2qhpMqYQ4Isk.XXyA8uvmFXyvgc1ds5 8jo0rW.Wsw.55Z.KTPaQ0gHXj0T3OGppYMELSJv1iuhPyyAnZpmq01CU0Qd5 CcRgdyW3HaqhmpXqJCS0Clo16zXA4HmAjR0tgIQrHRLc3D9N02AOzvmDgCb1 vCh0p00QeKVq8UNkcShPRxZFKi9khtkLhPBlXEKkhJ76zyDmHUxTY.dQHVVD 8D2hx7BxbqI9DINI8x5oR5Q8hYkZqHYQsmGNkaU77O2BnsEv5WxMEmzrBJ4Z h8zGCidgYPiZycZfnfaBp0Xb4tya2WMTN45W02JFcO1qq_UMJ9xPeqZhPEj. j9YvBAC8324GGF.c8eWcNB2VB34QHgTcVUl3.c0XUCuncls9Cyg4L7AoIdCi HvAklSzDDu9nW6732VEipV9FJ_JkDupDNQU2hfiPG.3OeF8GwTnVYnEn0EiZ aO0NCnZhXuLDcN3K7ml3846yRdASvzPFs9s4aJkzR0FkhVvptiMBEOdRkKdG wHWmvWpK4GTZpW4yU7CnKpW2MiWWn1MP0h_CCZFKs5.3mfmfPjPVIABN_RuU Q8ex5hdKnKlQiqK56LzcPRnYmNtrwdsUX9CYn9d6cPpXR_Bi5jrNJMNzdFvq lGO0CBT4QPe2V45U8PtpMitttuDA1cCvmyBPFswxNlL0jyX0a_W.vl0YW5.d HhDItpHhDxKRUscM28IR.exetq4QCzyM X-Originating-IP: [70.32.113.42] Authentication-Results: mta1267.mail.ac4.yahoo.com from=holsteinplaza.com; domainkeys=neutral (no sig); from=holsteinplaza.com; dkim=pass (ok) Received: from 127.0.0.1 (EHLO predator.axis80.com) (70.32.113.42) by mta1267.mail.ac4.yahoo.com with SMTP; Sat, 25 Jun 2011 18:30:11 -0700 Received: (qmail 1440 invoked by uid 48); 25 Jun 2011 21:30:09 -0400 To: [email protected] Subject: this is a test X-PHPMAILER-DKIM: phpmailer.worxware.com DKIM-Signature: v=1; a=rsa-sha1; q=dns/txt; l=203; s=auction; t=1309051808; c=relaxed/simple; h=From:To:Subject; d=holsteinplaza.com; [email protected]; z=From:=20Holstein=20Plaza=20Auctions=20<[email protected]> |To:[email protected] |Subject:=20this=20is=20a=20test; bh=B3Tw5AQb1va627KEoazuFEBZ0fg=; b=oQ5uFq+oekPTGhszyIritjuuIAi3qPNyeitu+aWMhdx3oC6O2j5hJsDFpK0sS5fms7QdnBkBcEzT0iekEvn9EfAdCkGZ2KrtEC0yv7QKQcrjXxy07GJpj9nq0LYbgOuPdw8mGvKxlRZ+jFBX0DRJm0xXFLkr+MEaILw7adHTCCM= Date: Sat, 25 Jun 2011 21:30:08 -0400 From: Holstein Plaza Auctions <[email protected]> Reply-to: Holstein Plaza Auctions <[email protected]> Message-ID: <[email protected]> X-Priority: 3 X-Mailer: PHPMailer 5.1 (phpmailer.sourceforge.net) MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="iso-8859-1" Content-Length: 195

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  • OpenVPN - client-to-client traffic working in one direction but not the other

    - by user42055
    I have the following VPN configuration: +------------+ +------------+ +------------+ | outpost |----------------| kino |----------------| guchuko | +------------+ +------------+ +------------+ OS: FreeBSD 6.2 OS: Gentoo 2.6.32 OS: Gentoo 2.6.33.3 Keyname: client3 Keyname: server Keyname: client1 eth0: 10.0.1.254 eth0: 203.x.x.x eth0: 192.168.0.6 tun0: 192.168.150.18 tun0: 192.168.150.1 tun0: 192.168.150.10 P-t-P: 192.166.150.17 P-t-P: 192.168.150.2 P-t-P: 192.168.150.9 Kino is the server and has client-to-client enabled. All three machines have ip forwarding enabled, by this on the gentoo boxes: net.ipv4.conf.all.forwarding = 1 And this on the FreeBSD box: net.inet.ip.forwarding: 1 In the server's "ccd" directory is the following files: client1: iroute 192.168.0.0 255.255.255.0 client3: iroute 10.0.1.0 255.255.255.0 The server config has these routes configured: push "route 192.168.0.0 255.255.255.0" push "route 10.0.1.0 255.255.255.0" route 192.168.0.0 255.255.255.0 route 10.0.1.0 255.255.255.0 Kino's routing table looks like this: 192.168.150.0 192.168.150.2 255.255.255.0 UG 0 0 0 tun0 10.0.1.0 192.168.150.2 255.255.255.0 UG 0 0 0 tun0 192.168.0.0 192.168.150.2 255.255.255.0 UG 0 0 0 tun0 192.168.150.2 0.0.0.0 255.255.255.255 UH 0 0 0 tun0 Outpost's like this: 192.168.150 192.168.150.17 UGS 0 17 tun0 192.168.0 192.168.150.17 UGS 0 2 tun0 192.168.150.17 192.168.150.18 UH 3 0 tun0 And Guchuko's like this: 192.168.150.0 192.168.150.9 255.255.255.0 UG 0 0 0 tun0 10.0.1.0 192.168.150.9 255.255.255.0 UG 0 0 0 tun0 192.168.150.9 0.0.0.0 255.255.255.255 UH 0 0 0 tun0 Now, the tests. Pings from Guchuko to Outpost's LAN IP work OK, as does the reverse - pings from Outpost to Guchuko's LAN IP. However... Pings from Outpost, to a machine on Guchuko's LAN work fine: .(( root@outpost )). (( 06:39 PM )) :: ~ :: # ping 192.168.0.3 PING 192.168.0.3 (192.168.0.3): 56 data bytes 64 bytes from 192.168.0.3: icmp_seq=0 ttl=63 time=462.641 ms 64 bytes from 192.168.0.3: icmp_seq=1 ttl=63 time=557.909 ms But a ping from Guchuko, to a machine on Outpost's LAN does not: .(( root@guchuko )). (( 06:43 PM )) :: ~ :: # ping 10.0.1.253 PING 10.0.1.253 (10.0.1.253) 56(84) bytes of data. --- 10.0.1.253 ping statistics --- 3 packets transmitted, 0 received, 100% packet loss, time 2000ms Guchuko's tcpdump of tun0 shows: 18:46:27.716931 IP 192.168.150.10 > 10.0.1.253: ICMP echo request, id 63009, seq 1, length 64 18:46:28.716715 IP 192.168.150.10 > 10.0.1.253: ICMP echo request, id 63009, seq 2, length 64 18:46:29.716714 IP 192.168.150.10 > 10.0.1.253: ICMP echo request, id 63009, seq 3, length 64 Outpost's tcpdump on tun0 shows: 18:44:00.333341 IP 192.168.150.10 > 10.0.1.253: ICMP echo request, id 63009, seq 3, length 64 18:44:01.334073 IP 192.168.150.10 > 10.0.1.253: ICMP echo request, id 63009, seq 4, length 64 18:44:02.331849 IP 192.168.150.10 > 10.0.1.253: ICMP echo request, id 63009, seq 5, length 64 So Outpost is receiving the ICMP request destined for the machine on it's subnet, but appears not be forwarding it. Outpost has gateway_enable="YES" in its rc.conf which correctly sets net.inet.ip.forwarding to 1 as mentioned earlier. As far as I know, that's all that's required to make a FreeBSD box forward packets between interfaces. Is there something else I could be forgetting ?

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  • iptables - quick safety eval & limit max conns over time

    - by Peter Hanneman
    Working on locking down a *nix server box with some fancy iptable(v1.4.4) rules. I'm approaching the matter with a "paranoid, everyone's out to get me" style, not necessarily because I expect the box to be a hacker magnet but rather just for the sake of learning iptables and *nix security more throughly. Everything is well commented - so if anyone sees something I missed please let me know! The *nat table's "--to-ports" point to the only ports with actively listening services. (aside from pings) Layer 2 apps listen exclusively on chmod'ed sockets bridged by one of the layer 1 daemons. Layers 3+ inherit from layer 2 in a similar fashion. The two lines giving me grief are commented out at the very bottom of the *filter rules. The first line runs fine but it's all or nothing. :) Many thanks, Peter H. *nat #Flush previous rules, chains and counters for the 'nat' table -F -X -Z #Redirect traffic to alternate internal ports -I PREROUTING --src 0/0 -p tcp --dport 80 -j REDIRECT --to-ports 8080 -I PREROUTING --src 0/0 -p tcp --dport 443 -j REDIRECT --to-ports 8443 -I PREROUTING --src 0/0 -p udp --dport 53 -j REDIRECT --to-ports 8053 -I PREROUTING --src 0/0 -p tcp --dport 9022 -j REDIRECT --to-ports 8022 COMMIT *filter #Flush previous settings, chains and counters for the 'filter' table -F -X -Z #Set default behavior for all connections and protocols -P INPUT DROP -P OUTPUT DROP -A FORWARD -j DROP #Only accept loopback traffic originating from the local NIC -A INPUT -i lo -j ACCEPT -A INPUT ! -i lo -d 127.0.0.0/8 -j DROP #Accept all outgoing non-fragmented traffic having a valid state -A OUTPUT ! -f -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT #Drop fragmented incoming packets (Not always malicious - acceptable for use now) -A INPUT -f -j DROP #Allow ping requests rate limited to one per second (burst ensures reliable results for high latency connections) -A INPUT -p icmp --icmp-type 8 -m limit --limit 1/sec --limit-burst 2 -j ACCEPT #Declaration of custom chains -N INSPECT_TCP_FLAGS -N INSPECT_STATE -N INSPECT #Drop incoming tcp connections with invalid tcp-flags -A INSPECT_TCP_FLAGS -p tcp --tcp-flags ALL ALL -j DROP -A INSPECT_TCP_FLAGS -p tcp --tcp-flags ALL NONE -j DROP -A INSPECT_TCP_FLAGS -p tcp --tcp-flags ACK,FIN FIN -j DROP -A INSPECT_TCP_FLAGS -p tcp --tcp-flags ACK,PSH PSH -j DROP -A INSPECT_TCP_FLAGS -p tcp --tcp-flags ACK,URG URG -j DROP -A INSPECT_TCP_FLAGS -p tcp --tcp-flags SYN,FIN SYN,FIN -j DROP -A INSPECT_TCP_FLAGS -p tcp --tcp-flags ALL FIN,PSH,URG -j DROP -A INSPECT_TCP_FLAGS -p tcp --tcp-flags FIN,RST FIN,RST -j DROP -A INSPECT_TCP_FLAGS -p tcp --tcp-flags SYN,RST SYN,RST -j DROP -A INSPECT_TCP_FLAGS -p tcp --tcp-flags ALL SYN,FIN,PSH,URG -j DROP -A INSPECT_TCP_FLAGS -p tcp --tcp-flags ALL SYN,RST,ACK,FIN,URG -j DROP #Accept incoming traffic having either an established or related state -A INSPECT_STATE -m state --state ESTABLISHED,RELATED -j ACCEPT #Drop new incoming tcp connections if they aren't SYN packets -A INSPECT_STATE -m state --state NEW -p tcp ! --syn -j DROP #Drop incoming traffic with invalid states -A INSPECT_STATE -m state --state INVALID -j DROP #INSPECT chain definition -A INSPECT -p tcp -j INSPECT_TCP_FLAGS -A INSPECT -j INSPECT_STATE #Route incoming traffic through the INSPECT chain -A INPUT -j INSPECT #Accept redirected HTTP traffic via HA reverse proxy -A INPUT -p tcp --dport 8080 -j ACCEPT #Accept redirected HTTPS traffic via STUNNEL SSH gateway (As well as tunneled HTTPS traffic destine for other services) -A INPUT -p tcp --dport 8443 -j ACCEPT #Accept redirected DNS traffic for NSD authoritative nameserver -A INPUT -p udp --dport 8053 -j ACCEPT #Accept redirected SSH traffic for OpenSSH server #Temp solution: -A INPUT -p tcp --dport 8022 -j ACCEPT #Ideal solution: #Limit new ssh connections to max 10 per 10 minutes while allowing an "unlimited" (or better reasonably limited?) number of established connections. #-A INPUT -p tcp --dport 8022 --state NEW,ESTABLISHED -m recent --set -j ACCEPT #-A INPUT -p tcp --dport 8022 --state NEW -m recent --update --seconds 600 --hitcount 11 -j DROP COMMIT *mangle #Flush previous rules, chains and counters in the 'mangle' table -F -X -Z COMMIT

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  • Duplicate GET request from multiple IPs - can anyone explain this?

    - by dwq
    We've seen a pattern in our webserver access logs which we're having problem explaining. A GET request appears in the access log which is a legitimate, but private, url as part of normal e-commerce website use (by private, we mean there is a unique key in a url form variable generated specifically for that customer session). Then a few seconds later we get hit with an identical request maybe 10-15 times within the space of a second. The duplicate requests are all from different IP addresses. The UserAgent for the duplicates are all the same (but different from the original request). The reverse DNS lookup on the IPs for all the duplicates requests resolve to the same large hosting company. Can anyone think of a scenario what would explain this? EDIT 1 Here's an example that's probably anonymised beyond being any actual use, but it might give an idea of the sort of pattern we're seeing (it's from a search query as they sometimes get duplicated too): xx.xx.xx.xx - - [21/Jun/2013:21:42:57 +0100] "GET /search.html?search=widget&Submit=Search HTTP/1.0" 200 5475 "http://www.ourdomain.com/index.html" "Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.1; WOW64; Trident/6.0)" xx.xx.xx.xx - - [21/Jun/2013:21:43:03 +0100] "GET /search.html?search=widget&Submit=Search HTTP/1.0" 200 5475 "" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_7) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.91 Safari/534.30" xx.xx.xx.xx - - [21/Jun/2013:21:43:03 +0100] "GET /search.html?search=widget&Submit=Search HTTP/1.0" 200 5475 "" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_7) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.91 Safari/534.30" xx.xx.xx.xx - - [21/Jun/2013:21:43:04 +0100] "GET /search.html?search=widget&Submit=Search HTTP/1.0" 200 5475 "" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_7) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.91 Safari/534.30" xx.xx.xx.xx - - [21/Jun/2013:21:43:04 +0100] "GET /search.html?search=widget&Submit=Search HTTP/1.0" 200 5475 "" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_7) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.91 Safari/534.30" xx.xx.xx.xx - - [21/Jun/2013:21:43:04 +0100] "GET /search.html?search=widget&Submit=Search HTTP/1.0" 200 5475 "" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_7) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.91 Safari/534.30" xx.xx.xx.xx - - [21/Jun/2013:21:43:04 +0100] "GET /search.html?search=widget&Submit=Search HTTP/1.0" 200 5475 "" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_7) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.91 Safari/534.30" xx.xx.xx.xx - - [21/Jun/2013:21:43:04 +0100] "GET /search.html?search=widget&Submit=Search HTTP/1.0" 200 5475 "" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_7) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.91 Safari/534.30" xx.xx.xx.xx - - [21/Jun/2013:21:43:04 +0100] "GET /search.html?search=widget&Submit=Search HTTP/1.0" 200 5475 "" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_7) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.91 Safari/534.30" xx.xx.xx.xx - - [21/Jun/2013:21:43:04 +0100] "GET /search.html?search=widget&Submit=Search HTTP/1.0" 200 5475 "" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_7) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.91 Safari/534.30" xx.xx.xx.xx - - [21/Jun/2013:21:43:04 +0100] "GET /search.html?search=widget&Submit=Search HTTP/1.0" 200 5475 "" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_7) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.91 Safari/534.30" UPDATE 2 Sometimes it is part of a checkout flow that's duplicated to I'd think twitter is unlikely.

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  • Bind9 Debian Not responding

    - by Marc
    Im trying to set up a webserver with Bind9, apache2 on Debian 6. I am trying to learn to do it manualy so I do not have any control panels or anything just the command line. I have a domain name lets call it www.example.com I want a virtual host setup so that I can have multiple websites with different names on my server. I have ns1.example.com and ns2.example.com registered at my servers IP (123.456.789.12). Below is my Bind9 named.conf.options options { directory "/var/cache/bind"; // If there is a firewall between you and nameservers you want // to talk to, you may need to fix the firewall to allow multiple // ports to talk. See http://www.kb.cert.org/vuls/id/800113 // If your ISP provided one or more IP addresses for stable // nameservers, you probably want to use them as forwarders. // Uncomment the following block, and insert the addresses replacing // the all-0's placeholder. // forwarders { // 0.0.0.0; // }; auth-nxdomain no; # conform to RFC1035 listen-on-v6 { any; }; }; This is the default I'm not sure if i was supposed to edit it. I didn't. Here is my named.conf.default-zones: // prime the server with knowledge of the root servers zone "." { type hint; file "/etc/bind/db.root"; }; // be authoritative for the localhost forward and reverse zones, and for // broadcast zones as per RFC 1912 zone "localhost" { type master; file "/etc/bind/db.local"; }; zone "127.in-addr.arpa" { type master; file "/etc/bind/db.127"; }; zone "0.in-addr.arpa" { type master; file "/etc/bind/db.0"; }; zone "255.in-addr.arpa" { type master; file "/etc/bind/db.255"; }; zone "example.com.com" { type master; file "etc/bind/example.com.db"; }; named.conf.local Is an empty file with a comment saying to do local configuration here. example.com.db looks like this: ; BIND data file for mywebsite.com ; $ORIGIN example.com. $TTL 604800 @ IN SOA ns1.example.com. [email protected]. ( 2009120101 ; Serial 604800 ; Refresh 86400 ; Retry 2419200 ; Expire 604800 ) ; Negative Cache TTL ; IN NS ns1.example.com. IN NS ns2.example.com. IN MX 10 mail.example.com. localhost IN A 127.0.0.1 example.com. IN A 123.456.789.12 ns1 IN A 123.456.789.12 ns2 IN A 123.456.789.12 www IN A 123.456.789.12 ftp IN A 123.456.789.12 mail IN A 123.456.789.12 boards IN CNAME www These are all settings I've found from various tutorials. Now when i go to intodns I get: You should already know that your NS records at your nameservers are missing, so here it is again: ns1.example.com ns2.example.com Can someone help me? I'm not sure what Im doing wrong.

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  • Configuring a PIX 506e for Asterisk

    - by orthogonal3
    Hi all! I'm having problems configuring a old Cisco PIX running 6.3 and wondered if anyone can lend a hand? Simply put I have a PIX 506e that I want to put in my VoIP data path. I can't update it and getting a compat version of Java for that version of PIX is tough so I can't log onto the web interface. The PIX straddles two networks..... 192.168.5.0 on the inside, ...50.0 on the outside both net masks are 255.255.255.0 I have a local Asterisk server cluster with a single service IP (<local asterisk>) SIP is on UDP 5060 and RTP (for the voip data) is on UDP 18000-18999 I know thats a big range but hey may as well. I need the 192.168.5.0 net to have web and ftp access for updates and the like. DHCP, DNS and NTP is already provided on that network so I don't need external DNS access. So I think I want the following rules: SIP or RTP from <my itsp> arriving at <outside voip ip> NATed to <local asterisk> SIP or RTP able to do the reverse route (should be covered by high sec - low sec??) HTTP and FTP access outbound for software update for the servers etc I have the following config at the minute - and I think I'm almost there (I hope)... interface ethernet0 auto interface ethernet1 auto nameif ethernet0 outside security0 nameif ethernet1 inside security100 enable password wouldyouliketobeapeppertoo encrypted passwd wouldyouliketobeapeppertoo encrypted hostname afirewall domain-name adomain fixup protocol dns maximum-length 512 fixup protocol ftp 21 fixup protocol h323 h225 1720 fixup protocol h323 ras 1718-1719 fixup protocol http 80 fixup protocol rsh 514 fixup protocol rtsp 554 fixup protocol sip 5060 fixup protocol sip udp 5060 fixup protocol skinny 2000 fixup protocol smtp 25 fixup protocol sqlnet 1521 fixup protocol tftp 69 access-list acl_ping permit icmp any any access-list voip permit ip host <my itsp> host <local asterisk> mtu outside 1500 mtu inside 1500 ip address outside <outside pix ip> 255.255.255.0 ip address inside <inside pix ip> 255.255.255.0 arp timeout 14400 global (outside) 1 <outside generic ip> nat (inside) 1 192.168.5.0 255.255.255.0 0 0 static (inside,outside) <outside voip ip> <local asterisk> netmask 255.255.255.255 0 0 static (outside,inside) <local asterisk> <outside voip ip> netmask 255.255.255.255 0 0 access-group acl_ping in interface outside access-group acl_ping in interface inside route outside 0.0.0.0 0.0.0.0 <my next hop router> 1 route outside <my itsp> 255.255.255.255 <my next hop router> 1 I think I just need a hand with the access-lists and NAT/static rules. Would anyone be able to help as I've RTFM'd the Cisco docs a few times and they're heavy. Wishing I'd completed my CCNA now! Thanks all for any help, Phil

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  • C# 4: The Curious ConcurrentDictionary

    - by James Michael Hare
    In my previous post (here) I did a comparison of the new ConcurrentQueue versus the old standard of a System.Collections.Generic Queue with simple locking.  The results were exactly what I would have hoped, that the ConcurrentQueue was faster with multi-threading for most all situations.  In addition, concurrent collections have the added benefit that you can enumerate them even if they're being modified. So I set out to see what the improvements would be for the ConcurrentDictionary, would it have the same performance benefits as the ConcurrentQueue did?  Well, after running some tests and multiple tweaks and tunes, I have good and bad news. But first, let's look at the tests.  Obviously there's many things we can do with a dictionary.  One of the most notable uses, of course, in a multi-threaded environment is for a small, local in-memory cache.  So I set about to do a very simple simulation of a cache where I would create a test class that I'll just call an Accessor.  This accessor will attempt to look up a key in the dictionary, and if the key exists, it stops (i.e. a cache "hit").  However, if the lookup fails, it will then try to add the key and value to the dictionary (i.e. a cache "miss").  So here's the Accessor that will run the tests: 1: internal class Accessor 2: { 3: public int Hits { get; set; } 4: public int Misses { get; set; } 5: public Func<int, string> GetDelegate { get; set; } 6: public Action<int, string> AddDelegate { get; set; } 7: public int Iterations { get; set; } 8: public int MaxRange { get; set; } 9: public int Seed { get; set; } 10:  11: public void Access() 12: { 13: var randomGenerator = new Random(Seed); 14:  15: for (int i=0; i<Iterations; i++) 16: { 17: // give a wide spread so will have some duplicates and some unique 18: var target = randomGenerator.Next(1, MaxRange); 19:  20: // attempt to grab the item from the cache 21: var result = GetDelegate(target); 22:  23: // if the item doesn't exist, add it 24: if(result == null) 25: { 26: AddDelegate(target, target.ToString()); 27: Misses++; 28: } 29: else 30: { 31: Hits++; 32: } 33: } 34: } 35: } Note that so I could test different implementations, I defined a GetDelegate and AddDelegate that will call the appropriate dictionary methods to add or retrieve items in the cache using various techniques. So let's examine the three techniques I decided to test: Dictionary with mutex - Just your standard generic Dictionary with a simple lock construct on an internal object. Dictionary with ReaderWriterLockSlim - Same Dictionary, but now using a lock designed to let multiple readers access simultaneously and then locked when a writer needs access. ConcurrentDictionary - The new ConcurrentDictionary from System.Collections.Concurrent that is supposed to be optimized to allow multiple threads to access safely. So the approach to each of these is also fairly straight-forward.  Let's look at the GetDelegate and AddDelegate implementations for the Dictionary with mutex lock: 1: var addDelegate = (key,val) => 2: { 3: lock (_mutex) 4: { 5: _dictionary[key] = val; 6: } 7: }; 8: var getDelegate = (key) => 9: { 10: lock (_mutex) 11: { 12: string val; 13: return _dictionary.TryGetValue(key, out val) ? val : null; 14: } 15: }; Nothing new or fancy here, just your basic lock on a private object and then query/insert into the Dictionary. Now, for the Dictionary with ReadWriteLockSlim it's a little more complex: 1: var addDelegate = (key,val) => 2: { 3: _readerWriterLock.EnterWriteLock(); 4: _dictionary[key] = val; 5: _readerWriterLock.ExitWriteLock(); 6: }; 7: var getDelegate = (key) => 8: { 9: string val; 10: _readerWriterLock.EnterReadLock(); 11: if(!_dictionary.TryGetValue(key, out val)) 12: { 13: val = null; 14: } 15: _readerWriterLock.ExitReadLock(); 16: return val; 17: }; And finally, the ConcurrentDictionary, which since it does all it's own concurrency control, is remarkably elegant and simple: 1: var addDelegate = (key,val) => 2: { 3: _concurrentDictionary[key] = val; 4: }; 5: var getDelegate = (key) => 6: { 7: string s; 8: return _concurrentDictionary.TryGetValue(key, out s) ? s : null; 9: };                    Then, I set up a test harness that would simply ask the user for the number of concurrent Accessors to attempt to Access the cache (as specified in Accessor.Access() above) and then let them fly and see how long it took them all to complete.  Each of these tests was run with 10,000,000 cache accesses divided among the available Accessor instances.  All times are in milliseconds. 1: Dictionary with Mutex Locking 2: --------------------------------------------------- 3: Accessors Mostly Misses Mostly Hits 4: 1 7916 3285 5: 10 8293 3481 6: 100 8799 3532 7: 1000 8815 3584 8:  9:  10: Dictionary with ReaderWriterLockSlim Locking 11: --------------------------------------------------- 12: Accessors Mostly Misses Mostly Hits 13: 1 8445 3624 14: 10 11002 4119 15: 100 11076 3992 16: 1000 14794 4861 17:  18:  19: Concurrent Dictionary 20: --------------------------------------------------- 21: Accessors Mostly Misses Mostly Hits 22: 1 17443 3726 23: 10 14181 1897 24: 100 15141 1994 25: 1000 17209 2128 The first test I did across the board is the Mostly Misses category.  The mostly misses (more adds because data requested was not in the dictionary) shows an interesting trend.  In both cases the Dictionary with the simple mutex lock is much faster, and the ConcurrentDictionary is the slowest solution.  But this got me thinking, and a little research seemed to confirm it, maybe the ConcurrentDictionary is more optimized to concurrent "gets" than "adds".  So since the ratio of misses to hits were 2 to 1, I decided to reverse that and see the results. So I tweaked the data so that the number of keys were much smaller than the number of iterations to give me about a 2 to 1 ration of hits to misses (twice as likely to already find the item in the cache than to need to add it).  And yes, indeed here we see that the ConcurrentDictionary is indeed faster than the standard Dictionary here.  I have a strong feeling that as the ration of hits-to-misses gets higher and higher these number gets even better as well.  This makes sense since the ConcurrentDictionary is read-optimized. Also note that I tried the tests with capacity and concurrency hints on the ConcurrentDictionary but saw very little improvement, I think this is largely because on the 10,000,000 hit test it quickly ramped up to the correct capacity and concurrency and thus the impact was limited to the first few milliseconds of the run. So what does this tell us?  Well, as in all things, ConcurrentDictionary is not a panacea.  It won't solve all your woes and it shouldn't be the only Dictionary you ever use.  So when should we use each? Use System.Collections.Generic.Dictionary when: You need a single-threaded Dictionary (no locking needed). You need a multi-threaded Dictionary that is loaded only once at creation and never modified (no locking needed). You need a multi-threaded Dictionary to store items where writes are far more prevalent than reads (locking needed). And use System.Collections.Concurrent.ConcurrentDictionary when: You need a multi-threaded Dictionary where the writes are far more prevalent than reads. You need to be able to iterate over the collection without locking it even if its being modified. Both Dictionaries have their strong suits, I have a feeling this is just one where you need to know from design what you hope to use it for and make your decision based on that criteria.

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  • Infinite loop during A* algorithm

    - by Tashu
    The A* algorithm is used by enemies to have a path to the goal. It's working but when sometimes I placed a tower in a grid (randomly) it produces a stack overflow error. The A* algorithm would iterate the enemy and find its path and pass the list to the enemy's path. I added debug logs and the list that I'm getting it looks like it would arrive from start cell to goal cell. Here's the log - 06-19 19:26:41.982: DEBUG/findEnemyPath, enemy X:Y(4281): X2.8256836:Y3.5 06-19 19:26:41.990: DEBUG/findEnemyPath, grid X:Y(4281): X3:Y2 06-19 19:26:41.990: DEBUG/START CELL ID:(4281): 38 06-19 19:26:41.990: DEBUG/GOAL CELL ID:(4281): 47 06-19 19:26:41.990: DEBUG/Best : 38(4281): passThrough:0.0 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 38 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 38 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 38 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 38 06-19 19:26:41.990: DEBUG/Best : 39(4281): passThrough:8.875 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 39 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 39 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 39 06-19 19:26:41.990: DEBUG/Best : 40(4281): passThrough:7.9375 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 40 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 40 06-19 19:26:41.990: DEBUG/Best : 52(4281): passThrough:8.9375 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 52 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 52 06-19 19:26:41.990: DEBUG/Best : 53(4281): passThrough:7.96875 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 53 06-19 19:26:41.990: DEBUG/Best : 28(4281): passThrough:8.9375 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 28 06-19 19:26:41.990: DEBUG/Best : 65(4281): passThrough:8.984375 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 65 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 65 06-19 19:26:41.990: DEBUG/Best : 66(4281): passThrough:7.9921875 06-19 19:26:41.990: DEBUG/Neighbor's Parent:(4281): 66 06-19 19:26:42.000: DEBUG/Best : 78(4281): passThrough:8.99609375 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 78 06-19 19:26:42.000: DEBUG/Best : 79(4281): passThrough:7.998046875 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 79 06-19 19:26:42.000: DEBUG/Best : 80(4281): passThrough:6.9990234375 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 80 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 80 06-19 19:26:42.000: DEBUG/Best : 81(4281): passThrough:5.99951171875 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 81 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 81 06-19 19:26:42.000: DEBUG/Best : 82(4281): passThrough:4.999755859375 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 82 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 82 06-19 19:26:42.000: DEBUG/Best : 83(4281): passThrough:3.9998779296875 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 83 06-19 19:26:42.000: DEBUG/Best : 71(4281): passThrough:2.99993896484375 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 71 06-19 19:26:42.000: DEBUG/Best : 59(4281): passThrough:1.99951171875 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 59 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 59 06-19 19:26:42.000: DEBUG/Neighbor's Parent:(4281): 59 06-19 19:26:42.000: DEBUG/Best : 47(4281): passThrough:0.99951171875 Then, the goal cell would be iterating its parent till start cell to break off the loop. private void populateBestList(Cell cell, List<Cell> bestList) { bestList.add(cell); if (cell.parent.start == false) { Log.d("ID:", ""+cell.id); Log.d("ParentID:", ""+cell.parent.id); populateBestList(cell.parent, bestList); } return; } The log with error above would show like this - 06-19 19:26:42.010: DEBUG/ID:(4281): 47 06-19 19:26:42.010: DEBUG/ParentID:(4281): 59 06-19 19:26:42.010: DEBUG/ID:(4281): 59 06-19 19:26:42.010: DEBUG/ParentID:(4281): 71 06-19 19:26:42.010: DEBUG/ID:(4281): 71 06-19 19:26:42.010: DEBUG/ParentID:(4281): 59 06-19 19:26:42.010: DEBUG/ID:(4281): 59 06-19 19:26:42.010: DEBUG/ParentID:(4281): 71 06-19 19:26:42.010: DEBUG/ID:(4281): 71 71 and 59 would switch over and goes on. I thought the grid is the issue due to the fact that enemies are using the single grid so I make the parent, start, and goal clear before starting the A* algorithm for an enemy. for(int i = 0; i < GRID_HEIGHT; i++) { for(int j = 0; j < GRID_WIDTH; j++) { grid[i][j].parent = null; grid[i][j].start = false; grid[i][j].goal = false; } } That didn't work. I thought it might be something related to this code, but not sure if I'm on right track - neighbor.parent = best; openList.remove(neighbor); closedList.remove(neighbor); openList.add(0, neighbor); Here's the code of the A* algorithm - private List<Cell> findEnemyPath(Enemy enemy) { for(int i = 0; i < GRID_HEIGHT; i++) { for(int j = 0; j < GRID_WIDTH; j++) { grid[i][j].parent = null; grid[i][j].start = false; grid[i][j].goal = false; } } List<Cell> openList = new ArrayList<Cell>(); List<Cell> closedList = new ArrayList<Cell>(); List<Cell> bestList = new ArrayList<Cell>(); int width = (int)Math.floor(enemy.position.x); int height = (int)Math.floor(enemy.position.y); width = (width < 0) ? 0 : width; height = (height < 0) ? 0 : height; Log.d("findEnemyPath, enemy X:Y", "X"+enemy.position.x+":"+"Y"+enemy.position.y); Log.d("findEnemyPath, grid X:Y", "X"+height+":"+"Y"+width); Cell start = grid[height][width]; Cell goal = grid[ENEMY_GOAL_HEIGHT][ENEMY_GOAL_WIDTH]; if(start.id != goal.id) { Log.d("START CELL ID: ", ""+start.id); Log.d("GOAL CELL ID: ", ""+goal.id); //Log.d("findEnemyPath, grid X:Y", "X"+start.position.x+":"+"Y"+start.position.y); start.start = true; goal.goal = true; openList.add(start); while(openList.size() > 0) { Cell best = findBestPassThrough(openList, goal); //Log.d("ID:", ""+best.id); openList.remove(best); closedList.add(best); if (best.goal) { System.out.println("Found Goal"); System.out.println(bestList.size()); populateBestList(goal, bestList); /* for(Cell cell : bestList) { Log.d("ID:", ""+cell.id); Log.d("ParentID:", ""+cell.parent.id); } */ Collections.reverse(bestList); Cell exit = new Cell(13.5f, 3.5f, 1, 1); exit.isExit = true; bestList.add(exit); //Log.d("PathList", "Enemy ID : " + enemy.id); return bestList; } else { List<Cell> neighbors = getNeighbors(best); for (Cell neighbor : neighbors) { if(neighbor.isTower) { continue; } if (openList.contains(neighbor)) { Cell tmpCell = new Cell(neighbor.position.x, neighbor.position.y, 1, 1); tmpCell.parent = best; if (tmpCell.getPassThrough(goal) >= neighbor.getPassThrough(goal)) { continue; } } if (closedList.contains(neighbor)) { Cell tmpCell = new Cell(neighbor.position.x, neighbor.position.y, 1, 1); tmpCell.parent = best; if (tmpCell.getPassThrough(goal) >= neighbor.getPassThrough(goal)) { continue; } } Log.d("Neighbor's Parent: ", ""+best.id); neighbor.parent = best; openList.remove(neighbor); closedList.remove(neighbor); openList.add(0, neighbor); } } } } Log.d("Cannot find a path", ""); return null; }

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  • How can I get penetration depth from Minkowski Portal Refinement / Xenocollide?

    - by Raven Dreamer
    I recently got an implementation of Minkowski Portal Refinement (MPR) successfully detecting collision. Even better, my implementation returns a good estimate (local minimum) direction for the minimum penetration depth. So I took a stab at adjusting the algorithm to return the penetration depth in an arbitrary direction, and was modestly successful - my altered method works splendidly for face-edge collision resolution! What it doesn't currently do, is correctly provide the minimum penetration depth for edge-edge scenarios, such as the case on the right: What I perceive to be happening, is that my current method returns the minimum penetration depth to the nearest vertex - which works fine when the collision is actually occurring on the plane of that vertex, but not when the collision happens along an edge. Is there a way I can alter my method to return the penetration depth to the point of collision, rather than the nearest vertex? Here's the method that's supposed to return the minimum penetration distance along a specific direction: public static Vector3 CalcMinDistance(List<Vector3> shape1, List<Vector3> shape2, Vector3 dir) { //holding variables Vector3 n = Vector3.zero; Vector3 swap = Vector3.zero; // v0 = center of Minkowski sum v0 = Vector3.zero; // Avoid case where centers overlap -- any direction is fine in this case //if (v0 == Vector3.zero) return Vector3.zero; //always pass in a valid direction. // v1 = support in direction of origin n = -dir; //get the differnce of the minkowski sum Vector3 v11 = GetSupport(shape1, -n); Vector3 v12 = GetSupport(shape2, n); v1 = v12 - v11; //if the support point is not in the direction of the origin if (v1.Dot(n) <= 0) { //Debug.Log("Could find no points this direction"); return Vector3.zero; } // v2 - support perpendicular to v1,v0 n = v1.Cross(v0); if (n == Vector3.zero) { //v1 and v0 are parallel, which means //the direction leads directly to an endpoint n = v1 - v0; //shortest distance is just n //Debug.Log("2 point return"); return n; } //get the new support point Vector3 v21 = GetSupport(shape1, -n); Vector3 v22 = GetSupport(shape2, n); v2 = v22 - v21; if (v2.Dot(n) <= 0) { //can't reach the origin in this direction, ergo, no collision //Debug.Log("Could not reach edge?"); return Vector2.zero; } // Determine whether origin is on + or - side of plane (v1,v0,v2) //tests linesegments v0v1 and v0v2 n = (v1 - v0).Cross(v2 - v0); float dist = n.Dot(v0); // If the origin is on the - side of the plane, reverse the direction of the plane if (dist > 0) { //swap the winding order of v1 and v2 swap = v1; v1 = v2; v2 = swap; //swap the winding order of v11 and v12 swap = v12; v12 = v11; v11 = swap; //swap the winding order of v11 and v12 swap = v22; v22 = v21; v21 = swap; //and swap the plane normal n = -n; } /// // Phase One: Identify a portal while (true) { // Obtain the support point in a direction perpendicular to the existing plane // Note: This point is guaranteed to lie off the plane Vector3 v31 = GetSupport(shape1, -n); Vector3 v32 = GetSupport(shape2, n); v3 = v32 - v31; if (v3.Dot(n) <= 0) { //can't enclose the origin within our tetrahedron //Debug.Log("Could not reach edge after portal?"); return Vector3.zero; } // If origin is outside (v1,v0,v3), then eliminate v2 and loop if (v1.Cross(v3).Dot(v0) < 0) { //failed to enclose the origin, adjust points; v2 = v3; v21 = v31; v22 = v32; n = (v1 - v0).Cross(v3 - v0); continue; } // If origin is outside (v3,v0,v2), then eliminate v1 and loop if (v3.Cross(v2).Dot(v0) < 0) { //failed to enclose the origin, adjust points; v1 = v3; v11 = v31; v12 = v32; n = (v3 - v0).Cross(v2 - v0); continue; } bool hit = false; /// // Phase Two: Refine the portal int phase2 = 0; // We are now inside of a wedge... while (phase2 < 20) { phase2++; // Compute normal of the wedge face n = (v2 - v1).Cross(v3 - v1); n.Normalize(); // Compute distance from origin to wedge face float d = n.Dot(v1); // If the origin is inside the wedge, we have a hit if (d > 0 ) { //Debug.Log("Do plane test here"); float T = n.Dot(v2) / n.Dot(dir); Vector3 pointInPlane = (dir * T); return pointInPlane; } // Find the support point in the direction of the wedge face Vector3 v41 = GetSupport(shape1, -n); Vector3 v42 = GetSupport(shape2, n); v4 = v42 - v41; float delta = (v4 - v3).Dot(n); float separation = -(v4.Dot(n)); if (delta <= kCollideEpsilon || separation >= 0) { //Debug.Log("Non-convergance detected"); //Debug.Log("Do plane test here"); return Vector3.zero; } // Compute the tetrahedron dividing face (v4,v0,v1) float d1 = v4.Cross(v1).Dot(v0); // Compute the tetrahedron dividing face (v4,v0,v2) float d2 = v4.Cross(v2).Dot(v0); // Compute the tetrahedron dividing face (v4,v0,v3) float d3 = v4.Cross(v3).Dot(v0); if (d1 < 0) { if (d2 < 0) { // Inside d1 & inside d2 ==> eliminate v1 v1 = v4; v11 = v41; v12 = v42; } else { // Inside d1 & outside d2 ==> eliminate v3 v3 = v4; v31 = v41; v32 = v42; } } else { if (d3 < 0) { // Outside d1 & inside d3 ==> eliminate v2 v2 = v4; v21 = v41; v22 = v42; } else { // Outside d1 & outside d3 ==> eliminate v1 v1 = v4; v11 = v41; v12 = v42; } } } return Vector3.zero; } }

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