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Search found 93 results on 4 pages for 'flooding'.

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• Windows Server 2008: Limit UDP/TCP packets per IP or ban

  - by WBAR

  How I can limit UDP/TCP packets per IP send to my host (or better PORT) per second or minute ? Would be nice to ban that IP for 12/24 hours or even for ever. I got Windows Server 2008 and I'm very poor in Windows administration but quite good in Linux. EDIT: By basic problem is that They sending a lot of rubbish UPD and TCP packets.. TCP packets without SYNCH, fragmented UDP packets so my servers stop responding.. So I need to cut off users (IPs) sending more than X packets per second. I need solution witch provides me, somehow, configurable: X packets of certain type (UDP, TCP or both - lets say parameter named Z ) are allowed to be received by IP on Y port, otherwise this packet should be DROPPED. My virtual hosts are hosted by VirtualBox and I'm able to forward all incoming packets certain type and certain port to the specific Virtual Host, but I need to DROP them before my VirtualBox receive them.

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• Network flooded with seemingly empty packets

  - by Adam Particka

  Let me preface this with the fact that I'm just a web developer at my company with little networking knowledge. Earlier today there was a department that lost all of their network connections so I popped open Wireshark and observed the influx of packets to my machine. There was normal traffic (ARP requests, etc.) coming in at ~50 packets every second. Then all of a sudden the log was flooded with packets arriving ~5000 a second. It looks as though they all contain the same data, just a looped sequence. We have someone here looking at it but I thought I would ask if anyone had seen anything like this before. Here's a selection from one of the captures in Wireshark. http://www.cloudshark.org/captures/06f950725c74

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• Using a randomly generated token for flood control.

  - by James P

  Basic setup of my site is: user enters a message on the homepage, hits enter and the message is sent though a AJAX request to a file called like.php where it echo's a link that gets sent back to the user. I have made the input disable when the user presses enter, but there's nothing stopping the user from just constantly flooding like.php with POST request and filling up my database. Someone here on SO told me to use a token system but didn't mention how. I've seen this being done before and from what I know it is effective. The only problem I have is how will like.php know it's a valid token? My code is this at the moment: $token = md5(rand(0, 9999) * 1000000); and the markup: <input type="hidden" name="token" value="<?php echo $token ?>" /> Which will send the token to like.php through POST. But how will like.php know that this is a valid token? Should I instead token something that's linked to the user? Like their IP address? Or perhaps token the current minute and check that it's the same minute in like.php... Any help on this amtter would be greatly appreciated, thanks. :)

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• How can I stop SipVicious ('friendly-scanner') from flooding my SIP server?

  - by a1kmm

  I run an SIP server which listens on UDP port 5060, and needs to accept authenticated requests from the public Internet. The problem is that occasionally it gets picked up by people scanning for SIP servers to exploit, who then sit there all day trying to brute force the server. I use credentials that are long enough that this attack will never feasibly work, but it is annoying because it uses up a lot of bandwidth. I have tried setting up fail2ban to read the Asterisk log and ban IPs that do this with iptables, which stops Asterisk from seeing the incoming SIP REGISTER attempts after 10 failed attempts (which happens in well under a second at the rate of attacks I'm seeing). However, SipVicious derived scripts do not immediately stop sending after getting an ICMP Destination Host Unreachable - they keep hammering the connection with packets. The time until they stop is configurable, but unfortunately it seems that the attackers doing these types of brute force attacks generally set the timeout to be very high (attacks continue at a high rate for hours after fail2ban has stopped them from getting any SIP response back once they have seen initial confirmation of an SIP server). Is there a way to make it stop sending packets at my connection?

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• Packet flooding while configuring a Debian L2TP/IPSec client?

  - by Joseph B.

  I'm currently at my wits end trying to configure an L2TP over IPSec VPN connection on my Debian using openswan and xl2tp box connecting to a server of unknown configuration. I've managed to successfully establish the connection and everything appears to be working well until I attempt to set the VPN connection as my default route, at which point I see a massive flood of packets simultaneously being transmitted (on the tune of ~1.5 GB in about 2min) until the server drops my connection. Prior to this network traffic on all my interfaces is minimal. According to iftop the majority of this traffic appears to be coming out of port 12, although I can't seem to figure out how to finger a specific process. If I instead just route traffic destined for 74.0.0.0/8 through it I'm able to access Google's servers through the VPN without issue. My xl2tp.conf file is: [lac vpn-nl] lns = example.vpn.com name = myusername pppoptfile = /etc/ppp/options.l2tpd.client My options.l2tpd.client file is: ipcp-accept-local ipcp-accept-remote refuse-eap require-mschap-v2 noccp noauth idle 1800 mtu 1410 mru 1410 usepeerdns lock name myusername password mypassword connect-delay 5000 And my routing table looks like: Destination Gateway Genmask Flags Metric Ref Use Iface 10.5.2.1 * 255.255.255.255 UH 0 0 0 ppp0 10.0.50.0 * 255.255.255.0 U 0 0 0 eth0 10.50.0.0 * 255.255.0.0 U 0 0 0 eth0 10.0.0.0 * 255.255.0.0 U 0 0 0 eth0 192.168.0.0 * 255.255.0.0 U 0 0 0 eth0 loopback * 255.0.0.0 U 0 0 0 lo default * 0.0.0.0 U 0 0 0 ppp0 I'm seeing absolutely nothing in auth.log and syslog during this time and can't seem to find any other log files it might be writing to. Any suggestions would be appreciated!

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• Alerts for when Login Failures Strike

  When repeated SQL Server login failures occur, a DBA should investigate. It could just be someone repeatedly typing in the wrong password. Worst case is a virus attack flooding your network with connection requests. Receiving an e-mail while login failures are occurring allows DBAs to investigate and fix the issue as soon as possible. So how is DBA notified of login failures without flooding their inbox?

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• KB972455 Windows Server Update Services 3.0 SP2

  - by Sniek NL

  Dear people, My Small Business Server 2003 failed to install this update SP2 for WSUS3.0. The update is not available for rollback. WSUS 3.0 is not to be found in my software configscreen or startup menu. Some files have been deleted from the hard drive and last but not least. The service will not run and .NET runtime errors keep flooding my logs. Question. How to remove an update or program which is not listed in add/remove software anymore. Since the update it fails to run WSUS. Event-id: 0 Category: none Source: .NET Runtime ERROR: This error keeps flooding my logs. I am hesitant to roll back to a system restore point since exchange is running on the same disks.... :)

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• How can I limit the number of open AF_INET sockets?

  - by Stefano Palazzo

  Is there a way to limit the number of concurretly open AF_INET sockets (only)? If so, how do I do it, and how will the networking behave if I'm above the limit? For background: My cheap commodity router is a bit eager to detect 'syn flooding'. When it does, it crashes (and doesn't automatically restart itself). I'm thinking limiting concurrent connections to around 1000 should keep it from bickering.

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• How Good SEO Can Help Promote Your Blog

  Are you a blogger with something to say, but need a bigger audience to hear you out? If so, then you're not alone. With millions of blogs flooding the Internet from points around the world, it can be tough to get your voice to stand out.

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• Nginx : Proper use of limit_req_zone and limit_req

  - by xperator

  I have 2 website running on VPS. Their purpose is sharing music files and publishing news. Both of them use wordpress. What I am trying is that I want to prevent little hackers from flooding the webserver and putting stress on the server to make it crash. The problem is that after using limit_req_zone and limit_req my website became very slow. Browsing Wordpress control panel takes a long long time. I tried changing values but it didn't improve much. I guess the problem is Wordpress because it's the only script I am using on both front and back end. Here is the last setting which seems to be more responsive than others : limit_req_zone $binary_remote_addr zone=flood:5m rate=10r/m; location ~ \.php$ { limit_req zone=flood burst=100 nodelay; } What are the optimal values that should be used in my case (wp) ? I want the website have it's normal behavior, On the other hand stopping lifeless people from flooding. Another question, Is it safe and enough to use limit_req only on php files ?

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• Should the MAC Tables on a switch Stack be the same between sessions?

  - by Kyle Brandt

  According to Cisco's documentation: "The MAC address tables on all stack members are synchronized. At any given time, each stack member has the same copy of the address tables for each VLAN." However, when logged into the switch I see the following: ny-swstack01#show mac ad | inc Total Total Mac Addresses for this criterion: 222 ny-swstack01#ses 2 ny-swstack01-2#show mac ad | inc Total Total Mac Addresses for this criterion: 229 ny-swstack01-2#exit ny-swstack01#ses 3 ny-swstack01-3#show mac ad | inc Total Total Mac Addresses for this criterion: 229 ny-swstack01-3#exit ny-swstack01#ses 4 ny-swstack01-4#show mac ad | inc Total Total Mac Addresses for this criterion: 235 ny-swstack01-4#exit ny-swstack01#show mac ad | inc Total Total Mac Addresses for this criterion: 222 Going back and forth this isn't just because it is changing over time either, within certain sessions there are entries that I don't seen from the master session. We are currently waiting to hear back on CIsco from this, but has anyone run into this before? I stumbled upon this when looking into Unicast flooding, one of the hosts that is a destination MAC of flooding has a MAC entry that appears in session 3, but nowhere else. Also, I checked an all sessions show the same aging time.

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• NGINX load balancer DOS itself

  - by cjaredrun

  I have been running a load balancing machine for a number of months now which has had no problems in the past. I got woken up to some downtime and I am seeing this a lot in syslog: TCP: Possible SYN flooding on port 80. Sending cookies. At which point Nginx takes up 100% of the cpu and doesn't come back down to normal for several minutes. I have it running on Ubuntu currently but I also was able to replicate on Debian 6.

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• Binary diff/patch for large files on linux?

  - by thejh

  I've got two partition images (A and B) and want to use them to create a patch that I can apply on A on another computer in order to get the new B image without flooding the network. I have the following requirements: works on linux can create diffs can use diffs to patch files can handle binary files can handle large files (a few hundred GB should work) no user interaction required (just a console application) ideally, should be able to read from/write to pipes (so that I can pipe into it from a gzip-compressed file and write to one) Does something like that exist?

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• Free forum engine with good anti-attack mechanisms

  - by macias

  I am looking for forum engine (for discussions) with good attack countermeasures built in. Windows (preferrably) or Linux. Free (as beer). I think about registration flooding and blocking user accounts attacks. For registration, such engine should have at least: captcha blocking mulitple registrations from the same IP providing login (for logging in) and user name (for displaying the author of the posts) For logging in: no blocking on multiple tries -- instead after X try sending via mail a token, the third piece needed for next login -- without it logging in will be impossible (it would be similar to activation process) The engine should be designed with two ideas in mind: protecting engine against attacks 0 penalty for decent users Thank you in advance for your help and recommendations.

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• Cisco 891w multiple VLAN configuration

  - by Jessica

  I'm having trouble getting my guest network up. I have VLAN 1 that contains all our network resources (servers, desktops, printers, etc). I have the wireless configured to use VLAN1 but authenticate with wpa2 enterprise. The guest network I just wanted to be open or configured with a simple WPA2 personal password on it's own VLAN2. I've looked at tons of documentation and it should be working but I can't even authenticate on the guest network! I've posted this on cisco's support forum a week ago but no one has really responded. I could really use some help. So if anyone could take a look at the configurations I posted and steer me in the right direction I would be extremely grateful. Thank you! version 15.0 service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname ESI ! boot-start-marker boot-end-marker ! logging buffered 51200 warnings ! aaa new-model ! ! aaa authentication login userauthen local aaa authorization network groupauthor local ! ! ! ! ! aaa session-id common ! ! ! clock timezone EST -5 clock summer-time EDT recurring service-module wlan-ap 0 bootimage autonomous ! crypto pki trustpoint TP-self-signed-3369945891 enrollment selfsigned subject-name cn=IOS-Self-Signed-Certificate-3369945891 revocation-check none rsakeypair TP-self-signed-3369945891 ! ! crypto pki certificate chain TP-self-signed-3369945891 certificate self-signed 01 (cert is here) quit ip source-route ! ! ip dhcp excluded-address 192.168.1.1 ip dhcp excluded-address 192.168.1.5 ip dhcp excluded-address 192.168.1.2 ip dhcp excluded-address 192.168.1.200 192.168.1.210 ip dhcp excluded-address 192.168.1.6 ip dhcp excluded-address 192.168.1.8 ip dhcp excluded-address 192.168.3.1 ! ip dhcp pool ccp-pool import all network 192.168.1.0 255.255.255.0 default-router 192.168.1.1 dns-server 10.171.12.5 10.171.12.37 lease 0 2 ! ip dhcp pool guest import all network 192.168.3.0 255.255.255.0 default-router 192.168.3.1 dns-server 10.171.12.5 10.171.12.37 ! ! ip cef no ip domain lookup no ipv6 cef ! ! multilink bundle-name authenticated license udi pid CISCO891W-AGN-A-K9 sn FTX153085WL ! ! username ESIadmin privilege 15 secret 5 $1$g1..$JSZ0qxljZAgJJIk/anDu51 username user1 password 0 pass ! ! ! class-map type inspect match-any ccp-cls-insp-traffic match protocol cuseeme match protocol dns match protocol ftp match protocol h323 match protocol https match protocol icmp match protocol imap match protocol pop3 match protocol netshow match protocol shell match protocol realmedia match protocol rtsp match protocol smtp match protocol sql-net match protocol streamworks match protocol tftp match protocol vdolive match protocol tcp match protocol udp class-map type inspect match-all ccp-insp-traffic match class-map ccp-cls-insp-traffic class-map type inspect match-any ccp-cls-icmp-access match protocol icmp class-map type inspect match-all ccp-invalid-src match access-group 100 class-map type inspect match-all ccp-icmp-access match class-map ccp-cls-icmp-access class-map type inspect match-all ccp-protocol-http match protocol http ! ! policy-map type inspect ccp-permit-icmpreply class type inspect ccp-icmp-access inspect class class-default pass policy-map type inspect ccp-inspect class type inspect ccp-invalid-src drop log class type inspect ccp-protocol-http inspect class type inspect ccp-insp-traffic inspect class class-default drop policy-map type inspect ccp-permit class class-default drop ! zone security out-zone zone security in-zone zone-pair security ccp-zp-self-out source self destination out-zone service-policy type inspect ccp-permit-icmpreply zone-pair security ccp-zp-in-out source in-zone destination out-zone service-policy type inspect ccp-inspect zone-pair security ccp-zp-out-self source out-zone destination self service-policy type inspect ccp-permit ! ! crypto isakmp policy 1 encr 3des authentication pre-share group 2 ! crypto isakmp client configuration group 3000client key 67Nif8LLmqP_ dns 10.171.12.37 10.171.12.5 pool dynpool acl 101 ! ! crypto ipsec transform-set myset esp-3des esp-sha-hmac ! crypto dynamic-map dynmap 10 set transform-set myset ! ! crypto map clientmap client authentication list userauthen crypto map clientmap isakmp authorization list groupauthor crypto map clientmap client configuration address initiate crypto map clientmap client configuration address respond crypto map clientmap 10 ipsec-isakmp dynamic dynmap ! ! ! ! ! interface FastEthernet0 ! ! interface FastEthernet1 ! ! interface FastEthernet2 ! ! interface FastEthernet3 ! ! interface FastEthernet4 ! ! interface FastEthernet5 ! ! interface FastEthernet6 ! ! interface FastEthernet7 ! ! interface FastEthernet8 ip address dhcp ip nat outside ip virtual-reassembly duplex auto speed auto ! ! interface GigabitEthernet0 description $FW_OUTSIDE$$ES_WAN$ ip address 10...* 255.255.254.0 ip nat outside ip virtual-reassembly zone-member security out-zone duplex auto speed auto crypto map clientmap ! ! interface wlan-ap0 description Service module interface to manage the embedded AP ip unnumbered Vlan1 arp timeout 0 ! ! interface Wlan-GigabitEthernet0 description Internal switch interface connecting to the embedded AP switchport trunk allowed vlan 1-3,1002-1005 switchport mode trunk ! ! interface Vlan1 description $ETH-SW-LAUNCH$$INTF-INFO-FE 1$$FW_INSIDE$ ip address 192.168.1.1 255.255.255.0 ip nat inside ip virtual-reassembly zone-member security in-zone ip tcp adjust-mss 1452 crypto map clientmap ! ! interface Vlan2 description guest ip address 192.168.3.1 255.255.255.0 ip access-group 120 in ip nat inside ip virtual-reassembly zone-member security in-zone ! ! interface Async1 no ip address encapsulation slip ! ! ip local pool dynpool 192.168.1.200 192.168.1.210 ip forward-protocol nd ip http server ip http access-class 23 ip http authentication local ip http secure-server ip http timeout-policy idle 60 life 86400 requests 10000 ! ! ip dns server ip nat inside source list 23 interface GigabitEthernet0 overload ip route 0.0.0.0 0.0.0.0 10.165.0.1 ! access-list 23 permit 192.168.1.0 0.0.0.255 access-list 100 remark CCP_ACL Category=128 access-list 100 permit ip host 255.255.255.255 any access-list 100 permit ip 127.0.0.0 0.255.255.255 any access-list 100 permit ip 10.165.0.0 0.0.1.255 any access-list 110 permit ip 192.168.0.0 0.0.5.255 any access-list 120 remark ESIGuest Restriction no cdp run ! ! ! ! ! ! control-plane ! ! alias exec dot11radio service-module wlan-ap 0 session Access point version 12.4 no service pad service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname ESIRouter ! no logging console enable secret 5 $1$yEH5$CxI5.9ypCBa6kXrUnSuvp1 ! aaa new-model ! ! aaa group server radius rad_eap server 192.168.1.5 auth-port 1812 acct-port 1813 ! aaa group server radius rad_acct server 192.168.1.5 auth-port 1812 acct-port 1813 ! aaa authentication login eap_methods group rad_eap aaa authentication enable default line enable aaa authorization exec default local aaa authorization commands 15 default local aaa accounting network acct_methods start-stop group rad_acct ! aaa session-id common clock timezone EST -5 clock summer-time EDT recurring ip domain name ESI ! ! dot11 syslog dot11 vlan-name one vlan 1 dot11 vlan-name two vlan 2 ! dot11 ssid one vlan 1 authentication open eap eap_methods authentication network-eap eap_methods authentication key-management wpa version 2 accounting rad_acct ! dot11 ssid two vlan 2 authentication open guest-mode ! dot11 network-map ! ! username ESIadmin privilege 15 secret 5 $1$p02C$WVHr5yKtRtQxuFxPU8NOx. ! ! bridge irb ! ! interface Dot11Radio0 no ip address no ip route-cache ! encryption vlan 1 mode ciphers aes-ccm ! broadcast-key vlan 1 change 30 ! ! ssid one ! ssid two ! antenna gain 0 station-role root ! interface Dot11Radio0.1 encapsulation dot1Q 1 native no ip route-cache bridge-group 1 bridge-group 1 subscriber-loop-control bridge-group 1 block-unknown-source no bridge-group 1 source-learning no bridge-group 1 unicast-flooding bridge-group 1 spanning-disabled ! interface Dot11Radio0.2 encapsulation dot1Q 2 no ip route-cache bridge-group 2 bridge-group 2 subscriber-loop-control bridge-group 2 block-unknown-source no bridge-group 2 source-learning no bridge-group 2 unicast-flooding bridge-group 2 spanning-disabled ! interface Dot11Radio1 no ip address no ip route-cache shutdown ! encryption vlan 1 mode ciphers aes-ccm ! broadcast-key vlan 1 change 30 ! ! ssid one ! antenna gain 0 dfs band 3 block channel dfs station-role root ! interface Dot11Radio1.1 encapsulation dot1Q 1 native no ip route-cache bridge-group 1 bridge-group 1 subscriber-loop-control bridge-group 1 block-unknown-source no bridge-group 1 source-learning no bridge-group 1 unicast-flooding bridge-group 1 spanning-disabled ! interface GigabitEthernet0 description the embedded AP GigabitEthernet 0 is an internal interface connecting AP with the host router no ip address no ip route-cache ! interface GigabitEthernet0.1 encapsulation dot1Q 1 native no ip route-cache bridge-group 1 no bridge-group 1 source-learning bridge-group 1 spanning-disabled ! interface GigabitEthernet0.2 encapsulation dot1Q 2 no ip route-cache bridge-group 2 no bridge-group 2 source-learning bridge-group 2 spanning-disabled ! interface BVI1 ip address 192.168.1.2 255.255.255.0 no ip route-cache ! ip http server no ip http secure-server ip http help-path http://www.cisco.com/warp/public/779/smbiz/prodconfig/help/eag access-list 10 permit 192.168.1.0 0.0.0.255 radius-server host 192.168.1.5 auth-port 1812 acct-port 1813 key ***** bridge 1 route ip

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• Optimized CSF LFD to miminize false positive emails on new install? Centos6.2 + ISPConfig3

  - by Damainman

  I have a remote dedicated server running CentOS 6.2 x64bit with ISPConfig3. This is a brand new install. Server Purpose: Basic LAMP Web Hosting with PureFTPD, BIND, CLAMAV, RKHunter. Any advice or link to a guide which will clearly explain how to optimize the CSF+LFD configuration is greatly appreciated. I am not exactly sure on where to start what I shouldn't loosen the restrictions on. At the moment my inbox is flooding with alerts from LFD such as: Suspicious process running under user postfix Excessive resource usage: haldaemon Account: haldaemon Resource: Process Time Exceeded: 1823 1800 (seconds) Executable: /usr/sbin/hald Command Line: hald PID: 1031 Killed: No Excessive resource usage: amavis Time: Tue Jun 5 12:43:35 2012 -0700 Account: amavis Resource: Virtual Memory Size Exceeded: 330 200 (MB) Executable: /usr/bin/perl Command Line: amavisd (virgin child) PID: 27931 Killed: No Excessive resource usage: apache Time: Tue Jun 5 12:35:33 2012 -0700 Account: apache Resource: Virtual Memory Size Exceeded: 437 200 (MB) Executable: /usr/sbin/httpd Command Line: /usr/sbin/httpd PID: 27286 Killed: No

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• What's the best way to Notify network users of outages or maintenance

  - by Dubs

  There are times when one of our applications is down for maintenance and we'd like to let our users know about it before they start flooding our help desk with calls. What's the best way to notify our users of an event on the network? Some users are on our intranet, while others log in from the Web. Is there an application they can install to which we can send notifications messages? I'm interested to hear what others have come up with to address this requirement. Thanks!

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• Enable: Asp.net connection pool monitoring with performance monitor

  - by BlackHawkDesign

  If this question is at the wrong forum, be free to tell me. I'm a c# developer, but I'm running in a system management issue here. Intro: Im suspecting that an asp.net application is having some issues with the connection pool and that the pool is flooding from time to time. So to make sure, I want to monitor the connection pool. After some searching I found this article : http://blog.idera.com/sql-server/performance-and-monitoring/ensure-proper-sql-server-connection-pooling-2/ Basicly it explains stuff about connection pools and how you can monitor the application pool with performance monitor. The problem: So I logged in to the asp.net server(The sql database is hosted on a different server) which hosts the website. Started performance monitor. But when I want to select 'Current # pooled and nonpooled connections', I have no instance to select. There fore I can't add it. Question How can I create/supply an instance so I can monitor the connection pool? Thanks in advance BHD

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• Slow performance over network (Ubuntu)

  - by Filipe Santos

  i did setup this NodeJs TCP Server and tested it with a message flooder. Just to see how the performance of the server is. While the message throughput is great if i run the server and the message flooder on the same computer (ubuntu), the throughput dramaticaly decreases if i start the server on computer1(ubuntu1) and the message flooder on computer2(also ubuntu). Both PC are on the same network. In fact, they are directly connected to each other. I started searching the internet for reasons and i suppose i need to tune TCP on both Ubuntu-pcs but until now i haven't been successfull at all. Has anyone experienced such problems, or could someone help me out? Thanks Here the flooding code: var net=require('net') var client = net.createConnection(5000, "10.0.0.2") client.addListener("connect", function(){ for(var i = 0; i < 1000; i++) { client.write("message "); } })

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• Just one client bound to address and port: does it make a difference broadcast versus unicast in terms of overhead?

  - by chrisapotek

  Scenario: I am implementing failed over for a network node, so my idea is to make the master node listens on a broadcast ip address and port. If the master node fails, another failover node will start listening on this broadcast address (and port) and take over. Question: My concern is that I will be using a broadcast IP address just for a single node: the master. The failover node only binds if the master fails, in other words, almost never. In terms of network/traffic overhead, is it bad to talk to a single node through a broadcast address or the network somehow is smart enough to know that nobody else is listening to this broadcast address and kind of treat it as a unicast in terms of overhead? My concern is that I will be flooding my network with packets from this broadcast address even thought I am just really talking to a single node (the master). But I can't use unicast because the failover node has to be able to pick up the master stream quickly and transparently in case it fails.

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• TCP connection stuck in SYN_RECV state despite ACK received, Linux 2.6.18, embedded, ARM

  - by waynix

  My client cannot connect to my protocol port (TCP) after some network glitches, even though all other protocols (telnet/HTTP/FTP) work fine. netstat shows that my server is listening and tcpdump on the server shows all 3 packets are exchanged: 18:29:16.578964 IP 10.9.59.10.3355 10.9.43.131.5084: S 2602965897:2602965897(0) win 65535 <mss 1460,nop,nop,sackOK> 18:29:16.579107 IP 10.9.43.131.5084 10.9.59.10.3355: S 3464857909:3464857909(0) ack 2602965898 win 5840 <mss 1460,nop,nop,sackOK> 18:29:16.579284 IP 10.9.59.10.3355 10.9.43.131.5084: . ack 1 win 65535 But somehow netstat -t shows the connection still in SYN_RECV, as if the ack is not seen by the TCP state machine. I have to restart my server to get it to work. syncookie is not enabled, and I know from client code behavior and tcpdump that there is no SYN flooding. Help much appreciated.

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• Windows 8 mail cause event 529 when connect to exchange

  - by holian

  I set my company exchange mailbox in Windows 8.1 mail. (outsite). Everything works fine, but after i start the Windows 8.1 mail i get event with id 529 in the security log continously. Reason: Unknown user name or bad password Username: [email protected] range: Type of login: 8 Logon Process: Advapi Authentication Package: Negotiate Workstation Name: SERVERNAME Caller User Name: SERVERNAME $ Calling range BAR NUL Caller Logon ID: (0x0, 0x3E7) Caller Process ID: 4384 Transmitted services: - Source Network Address: 56.43.213.122 Source Port: 55 698 If i close windows mail, events stop flooding the security log in the server. Connection parameters in windwos 8: email:[email protected] password domain:company.local username:myemail server:mydomain.dyndns.org SSL:yes. Any idea whats the problem? I can check my mail, with the same setting on my android phone without any problem. Thank you

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• switch OFF syn cookies

  - by Nick

  We have several servers they have public IP's, but work together (one is with Load Balancer, orther with Apache Web server, other with MySQL and so on. Most of the ports are fire-walled, so only "local" servers can be connect there. However ALL servers have some ports that must be publicly open. We have SYN Cookies enabled and from time to time we got: possible SYN flooding on port 8080. Sending cookies. Port 8080 is not public. How we can switch OFF SYN Cookies for some ports (e.g. 8080, 3306 etc) or from some sources (e.g. our servers), but in same time SYN Cookies to be switched ON for all other ports, e.g. port 80. We found this similar problem, except our servers are with public IP's: SYN cookies on internal machines

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• Best 'free' option for alert notifications other than email/SMS

  - by Eureka Ikara

  Looking for a Linux script solution that can send alerts to a service such as Twitter, Skype or Google Talk and sends to Android and iPhone clients. Have found twurl for Twitter with previous Bash scripts using curl no longer supported. But twurl looks promising. But haven't seen how to get Android Twitter client to make a distinctive sound when a tweet arrives. Found some info about Skype4Py from several years ago that supports Skype Chats. But doesn't look like it is currently supported. Have tried a few CLI clients for XMPP/Google Talk including xmpp4r-simple and freetalk, but found xmpp4r-simple buggy and freetalk succeeded in sending one chat message, but most never arrived. Whatever is used needs to support Android and iPhone clients. Reason why email is problematic is that Gmail gets very upset when emails start flooding in every minute as a result of alerts. Any suggestions?

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• West Palm Beach Dev Group August 2012 Meeting Recap

  - by Sam Abraham

  As the saying goes, it’s better late than never. Such is the case with my overdue West Palm Beach Dev Group August 2012 meeting report. Our August meeting was full of both knowledge and adventure. It comes as no surprise that the knowledge was brought to us by our favorite DotNetNuke Technical Evangelist, Will Strohl. Will introduced and thoroughly presented the new social features in DNN 6.2. Unfortunately, our meeting date coincided with Hurricane Isaac having just passed us by. Aside from road closures and floods that kept public schools closed for two days, our meeting host, PC Professor, had to close the school the day of our meeting on a short notice due to flooding which we found out about at midnight on the day of the event.  This left us scrambling to find an available alternate meeting location close enough to our original venue. Cancelling the meeting was always an option, but we opted to keep it as the very last resort. Luckily, we were fortunate to find a meeting room at the Hampton Inn only a few minutes away from our original location. Having heard of our challenge, our event sponsor, Applied Innovations, stepped-in and covered the meeting room cost in addition to the food and beverages. We would like to thank our volunteers and sponsors who made that event a success: Jess Coburn, CEO and Cara Pluff, Director of Sales at Applied Innovations, Dave Noderer for suggesting the alternate venue and Venkat Subramanian for his hard work keeping our members informed of the venue change and for being our event photographer.   We look forward to seeing you at our upcoming meetings: -September 25th, 2012 with Jonas Stawski, Microsoft MVP -October 23rd, 2012 with our Microsoft Developer Evangelist, Joe “DevFish” Healy -Ending an exciting year will be our November 27th meeting with Dycom Industries’ Senior Software Developer, Tom Huynh.   All the best, --Sam

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