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• Oracle Brings Java to iOS Devices (and Android too)

  - by Shay Shmeltzer

  Java developer, did you ever wish that you can take your Java skills and apply them to building applications for iOS mobile devices? Well, now you can! With the new Oracle ADF Mobile solution, Oracle has created a unique technology that allows developers to use the Java language and develop applications that install and run on both iOS and Android mobile devices. The solution is based on a thin native container that installs as part of your application. The container is able to run the same application you develop unchanged on both Android and iOS devices. One part of the container is a headless lightweight JVM based on the Java ME CDC technology. This allows the execution of Java code on your mobile device. Java is used for building business logic, accessing local SQLite encrypted database, and invoking and interacting with remote services. Java concept on the UI too To further help transition Java developers to mobile developers, ADF Mobile borrows familiar concepts from the world of JSF to make the UI development experience simpler. The user interface layer of Oracle ADF Mobile is rendered with HTML5 which delivers native user experience on the devices, including animations and gesture support. Using a set of rich components, developers can create mobile pages without needing to write low level HTML5 and JavaScript code. The components cover everything from simple controls such as text fields, date pickers, buttons and links, to advanced data visualization components such as graphs, gauges and maps, and including unique mobile UI patterns such as lists, and toggle selectors. Want to see the components in action? Access this demo instance from your mobile device. Need to further customize the look and feel? You can use CSS3 to achieve this. A controller layer - similar in functionality to the JSF controller - allows developer to simplify the way they build navigation between pages. The logic behind the pages is written in managed beans with various scopes – again similar to the JSF approach. Need to interact with device features like camera, SMS, Contacts etc? Oracle conveniently packaged access to these services in a set of services that you can just drag and drop into your pages as buttons and links, or code into your managed beans Java calls to activate. Underneath the covers this layer is implemented using the open source phonegap solution. With the new Oracle ADF Mobile solution, transferring your Java skills into the Mobile world has become much easier. Check out this development experience demo. And then go and download JDeveloper and the ADF Mobile extension and try it out on your own. For more on ADF Mobile, see the ADF Mobile OTN page.

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• Inherit one instance variable from the global scope

  - by Julian

  I'm using Curses to create a command line GUI with Ruby. Everything's going well, but I have hit a slight snag. I don't think Curses knowledge (esoteric to be fair) is required to answer this question, just Ruby concepts such as objects and inheritance. I'm going to explain my problem now, but if I'm banging on, just look at the example below. Basically, every Window instance needs to have .close called on it in order to close it. Some Window instances have other Windows associated with it. When closing a Window instance, I want to be able to close all of the other Window instances associated with it at the same time. Because associated Windows are generated in a logical fashion, (I append the name with a number: instance_variable_set(self + integer, Window.new(10,10,10,10)) ), it's easy to target generated windows, because methods can anticipate what assosiated windows will be called, (I can recreate the instance variable name from scratch, and almost query it: instance_variable_get(self + integer). I have a delete method that handles this. If the delete method is just a normal, global method (called like this: delete_window(@win543) then everything works perfectly. However, if the delete method is an instance method, which it needs to be in-order to use the self keyword, it doesn't work for a very clear reason; it can 'query' the correct instance variable perfectly well (instance_variable_get(self + integer)), however, because it's an instance method, the global instances aren't scoped to it! Now, one way around this would obviously be to simply make a global method like this: delete_window(@win543). But I have attributes associated with my window instances, and it all works very elegantly. This is very simplified, but it literally translates the problem exactly: class Dog def speak woof end end def woof if @dog_generic == nil puts "@dog_generic isn't scoped when .woof is called from a class method!\n" else puts "@dog_generic is scoped when .woof is called from the global scope. See:\n" + @dog_generic end end @dog_generic = "Woof!" lassie = Dog.new lassie.speak #=> @dog_generic isn't scoped when .woof is called from an instance method!\n woof #=> @dog_generic is scoped when .woof is called from the global scope. See:\nWoof! TL/DR: I need lassie.speak to return this string: "@dog_generic is scoped when .woof is called from the global scope. See:\nWoof!" @dog_generic must remain as an insance variable. The use of Globals or Constants is not acceptable. Could woof inherit from the Global scope? Maybe some sort of keyword: def woof < global # This 'code' is just to conceptualise what I want to do, don't take offence! end Is there some way the .woof method could 'pull in' @dog_generic from the global scope? Will @dog_generic have to be passed in as a parameter?

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• What is going on in this SAT/vector projection code?

  - by ssb

  I'm looking at the example XNA SAT collision code presented here: http://www.xnadevelopment.com/tutorials/rotatedrectanglecollisions/rotatedrectanglecollisions.shtml See the following code: private int GenerateScalar(Vector2 theRectangleCorner, Vector2 theAxis) { //Using the formula for Vector projection. Take the corner being passed in //and project it onto the given Axis float aNumerator = (theRectangleCorner.X * theAxis.X) + (theRectangleCorner.Y * theAxis.Y); float aDenominator = (theAxis.X * theAxis.X) + (theAxis.Y * theAxis.Y); float aDivisionResult = aNumerator / aDenominator; Vector2 aCornerProjected = new Vector2(aDivisionResult * theAxis.X, aDivisionResult * theAxis.Y); //Now that we have our projected Vector, calculate a scalar of that projection //that can be used to more easily do comparisons float aScalar = (theAxis.X * aCornerProjected.X) + (theAxis.Y * aCornerProjected.Y); return (int)aScalar; } I think the problems I'm having with this come mostly from translating physics concepts into data structures. For example, earlier in the code there is a calculation of the axes to be used, and these are stored as Vector2, and they are found by subtracting one point from another, however these points are also stored as Vector2s. So are the axes being stored as slopes in a single Vector2? Next, what exactly does the Vector2 produced by the vector projection code represent? That is, I know it represents the projected vector, but as it pertains to a Vector2, what does this represent? A point on a line? Finally, what does the scalar at the end actually represent? It's fine to tell me that you're getting a scalar value of the projected vector, but none of the information I can find online seems to tell me about a scalar of a vector as it's used in this context. I don't see angles or magnitudes with these vectors so I'm a little disoriented when it comes to thinking in terms of physics. If this final scalar calculation is just a dot product, how is that directly applicable to SAT from here on? Is this what I use to calculate maximum/minimum values for overlap? I guess I'm just having trouble figuring out exactly what the dot product is representing in this particular context. Clearly I'm not quite up to date on my elementary physics, but any explanations would be greatly appreciated.

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• How do you conquer the challenge of designing for large screen real-estate?

  - by Berin Loritsch

  This question is a bit more subjective, but I'm hoping to get some new perspective. I'm so used to designing for a certain screen size (typically 1024x768) that I find that size to not be a problem. Expanding the size to 1280x1024 doesn't buy you enough screen real estate to make an appreciable difference, but will give me a little more breathing room. Basically, I just expand my "grid size" and the same basic design for the slightly smaller screen still works. However, in the last couple of projects my clients were all using 1080p (1920x1080) screens and they wanted solutions to use as much of that real estate as possible. 1920 pixels across provides just under twice the width I am used to, and the wide screen makes some of my old go to design approaches not to work as well. The problem I'm running into is that when presented with so much space, I'm confronted with some major problems. How many columns should I use? The wide format lends itself to a 3 column split with a 2:1:1 split (i.e. the content column bigger than the other two). However, if I go with three columns what do I do with that extra column? How do I make efficient use of the screen real estate? There's a temptation to put everything on the screen at once, but too much information actually makes the application harder to use. White space is important to help make sense of complex information, but too much makes related concepts look too separate. I'm usually working with web applications that have complex data, and visualization and presentation is key to making sense of the raw data. When your user also has a large screen (at least 24"), some information is out of eye sight and you need to move the pointer a long distance. How do you make sure everything that's needed stays within the visual hot points? Simple sites like blogs actually do better when the width is constrained, which results in a lot of wasted real estate. I kind of wonder if having the text box and the text preview side by side would be a big benefit for the admin side of that type of screen? (1:1 two column split). For your answers, I know almost everything in design is "it depends". What I'm looking for is: General principles you use How your approach to design has changed I'm finding that i have to retrain myself how to work with this different format. Every bump in resolution I've worked through to date has been about 25%: 640 to 800 (25% increase), 800 to 1024 (28% increase), and 1024 to 1280 (25% increase). However, the jump from 1280 to 1920 is a good 50% increase in space--the equivalent from jumping from 640 straight to 1024. There was no commonly used middle size to help learn lessons more gradually.

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• FREE EBus (ATG) webcast on Troubleshooting Invalid Objects

  - by cwarticki

  v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} Normal 0 false false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} E-Business Suite Applications Technology Group (ATG) Advisor Webcast Program Invitation : Advisor Webcast December 2012 In December 2012 we have scheduled an Advisor Webcast, where we want to give you a closer look into the invalid objects in an E-Business Suite Environment. E-Business Suite – Troubleshooting invalid objects Agenda : · Introduction · Activities that generate invalid objects · EBS Architecture · EBS Patching Concepts · Troubleshooting Invalid Objects · References EMEA Session : o Tuesday December 11th, 2012 o at 09:00 AM UK / 10:00 AM CET / 13:30 India / 17:00 Japan / 18:00 Australia o Details & Registration : Note 1501696.1 o Direct link to register in WebEx US Session : o Wednesday December 12th, 2012 o at 18:00 UK / 19:00 CET / 10:00 AM Pacific / 11:00 AM Mountain/ 01:00 PM Eastern o Details & Registration : Note 1501697.1 o Direct link to register in WebEx If you have any question about the schedules or if you have a suggestion for an Advisor Webcast to be planned in future, please send an E-Mail to Ruediger Ziegler.

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• The term "interface" in C++

  - by Flexo

  Java makes a clear distinction between class and interface. (I believe C# does also, but I have no experience with it). When writing C++ however there is no language enforced distinction between class and interface. Consequently I've always viewed interface as a workaround for the lack of multiple inheritance in Java. Making such a distinction feels arbitrary and meaningless in C++. I've always tended to go with the "write things in the most obvious way" approach, so if in C++ I've got what might be called an interface in Java, e.g.: class Foo { public: virtual void doStuff() = 0; ~Foo() = 0; }; and I then decided that most implementers of Foo wanted to share some common functionality I would probably write: class Foo { public: virtual void doStuff() = 0; ~Foo() {} protected: // If it needs this to do its thing: int internalHelperThing(int); // Or if it doesn't need the this pointer: static int someOtherHelper(int); }; Which then makes this not an interface in the Java sense anymore. Instead C++ has two important concepts, related to the same underlying inheritance problem: virtual inhertiance Classes with no member variables can occupy no extra space when used as a base "Base class subobjects may have zero size" Reference Of those I try to avoid #1 wherever possible - it's rare to encounter a scenario where that genuinely is the "cleanest" design. #2 is however a subtle, but important difference between my understanding of the term "interface" and the C++ language features. As a result of this I currently (almost) never refer to things as "interfaces" in C++ and talk in terms of base classes and their sizes. I would say that in the context of C++ "interface" is a misnomer. It has come to my attention though that not many people make such a distinction. Do I stand to lose anything by allowing (e.g. protected) non-virtual functions to exist within an "interface" in C++? (My feeling is the exactly the opposite - a more natural location for shared code) Is the term "interface" meaningful in C++ - does it imply only pure virtual or would it be fair to call C++ classes with no member variables an interface still?

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• Can I subnet a subnet?

  - by Portman

  Apologies in advance for the botched terminology. I have read the Server Fault Subnet Wiki but this is more of an ISP question. I currently have a /27 block of public IPs. I use give my router the first address in this pool and then use 1-to-1 NAT for all the servers behind the firewall, so that they each get their own public IP. The router/firewall is currently using (actual addresses removed to protect the guilty): IP Address: XXX.XXX.XXX.164 Subnet mask: 255.255.255.224 Gateway: XXX.XXX.XXX.161 What I would like to do is break out my subnet into two separate /28 subnets. And do this in a way that is transparent to the ISP (i.e., they see me as continuing to operate a single /27). Currently, my topology looks like: ISP | [Router/Firewall] | [Managed Ethernet Switch] / \ \ [Server1] [Server2] [Server3] (etc) Instead, I would like it to look like: ISP | [Switch] / \ [Router1] [Router2] | | | | [S1] [S2] [S3] [S4] (etc) As you can see, this would partition me into two separate networks. I'm struggling with what the correct IP settings would be on Router1 and Router2. Here's what I have right now: Router1 Router2 IP Address: XXX.XXX.XXX.164 XXX.XXX.XXX.180 Subnet mask: 255.255.255.240 255.255.255.240 Gateway: XXX.XXX.XXX.161 XXX.XXX.XXX.161 Note that normally you would expect Router2 to have a gateway of .177, but I'm trying to get them both to use the gateway originally given to me by the ISP. Is subnetting like this in fact possible, or am I completely botching the most basic concepts?

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• Choosing the right TV tuner - USB or PCI TV tuners, hardware/software, DVB? Hybrid/combo/analog?

  - by Nucleon

  Greetings, I'll start with some background information so you know what I'm trying to accomplish and then get to my question. I work at a Television station in the US and we are working on setting up an online DVR/Podcast system for all of our newscasts. So basically we would be recording every newscast in HD, encoding it to flv/h.264 for viewing in a browser on flash compatible and iphone/ipad devices, eventually migrating to WebM when it's browser compliant. This task is theoretically pretty simple as it all it involves is a TV tuner device and a program like VLC, MythTV or whatever to schedule and dump it to a file, encode it with VLC/FFMPEG and push it to the streaming server. Now to the hardware, in order to accomplish that task, should I use an internal PCI tuner or a USB 2.0 tuner? Is there a difference? The bus speeds of both are not too far apart, and is the bus speed really relevant in this case? Does it matter if the device has a hardware encoder or a software encoder? On many sites the USB was recommended for ease of set up and use, but would it overly task a processor, or is that not a concern as long as it's a decent PC (at least duo core, 6gb ram). What's the difference between the stick USB and the Box USBs? To my understanding analog is basically gone in the US, so we would want a hybrid or combo tuner correct? How do those differ from DVB? Are there any other features or concepts which I am missing which may influence the recommended product. It would be ideal if the device which could work in both Linux and a Windows environment, to my knowledge most Hauppauge are? Example 1: PCI Hauppage http://www.newegg.com/Product/Product.aspx?Item=N82E16815116033 Example 2: USB 2.0 Box http://www.newegg.com/Product/Product.aspx?Item=N82E16815116029 Example 3: USB 2.0 Stick http://www.newegg.com/Product/Product.aspx?Item=N82E16815116031 Any guidance from the Superusers would be much appreciated!

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• How does enterprise failover, such as with google.com, actually work?

  - by Alex Regan

  We have a few fedora systems that are configured for web, FTP, and email services. We'd like to mirror these services, so that we can provide near 100% reliability for our users. I'm a fairly experienced Linux administrator, but don't have much experience with redundant systems. What is the best way to do this? How does google and amazon do it? Google.com resolves to multiple IP addresses, but if my local desktop caches one of the IPs that are unreachable, I'm going to get a failed connection message. How do they prevent that from happening? If one of their servers goes down, how is it automatically redirected to another system, without the end-user ever knowing it? I understand there are failover devices, but they're only for failing over the system itself, not a complete network. Let's say we have the worst-case scenario, such as my primary system becomes inaccessible. What are the fundamental components that are used on Linux systems to provide this capability? I'm looking for concepts, or approaches, not answers like "check out openstack". What are the actual pieces that make up the solution? What has to be done to implement this capability? Hopefully my question is clear. I'd like to know what the pieces are that make up a failover system and what approach is taken by successful organizations that implement it. Thanks again, Alex

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• Troubleshooting iptables and configuring it to drop the priority of long-term connections

  - by intuited

  I'm somewhat familiar with the general concepts of iptables, and would like to learn it in more detail. I'm hoping that my learning experience can also be useful. The situation: I'm running dd-wrt on my router. Despite its purported QoS skills, I'm still seeing connection latency shoot up hugely whenever there's an ongoing http connection, eg some large download. Under such conditions, it can take 10 seconds or more to load a basic webpage; sometimes the connections are dropped entirely. I've tried adjusting the parameters, dropping the allotted bandwidth for up and download to well under my limit, but nothing seems to work. dd-wrt is configured to use HTB as the QoS algorithm; HFSC, although presented as an option, seems to cause the router to crash, and is rumoured to not actually work on any linux system. I'd like to be able to troubleshoot this issue and hopefully improve the settings that dd-wrt is using, but I'm finding the learning curve a bit overwhelming. For starters I am not sure what HTB actually specifies: is this a set of iptables commands, or do some of those commands specify how HTB is to be used? I would like it to prioritize based on protocol the way that it already supposed to, and in addition I'd like to have it drop the priority of connections which have a high total byte count, say over 400KB. Also tips on utilities that can be run under dd-wrt to get more info on what's going on in there are appreciated. I've tried to get iftop to work but there were issues running curses. I'm leaning towards replacing dd-wrt with openwrt; comments on this strategy are also welcome. I suspect that I would be well advised to get a second router as a standin before trying that. It may be worth noting that my total bandwidth is pretty limited (256Kbit/s).

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• How to use DNS/Hostnames or Other ways to resolve to a specific IP:Port

  - by tomaszs

  This is a Canonical Question about DNS/Hostnames resolution to IPs/Ports Example 1 I'm running a web server on port 80 and another on port 87. I would like to use DNS so that www.example.com goes to port 87. How can I accomplish this using DNS only? Example 2 I'm running a service on my server on a non-standard port. How can I get clients to connect to this non-standard port automatically? Can I use DNS? Is there some application specific support where DNS could indicate the IP and Port? Example 3 Do some application protocols specifically support hostname awareness, and allow special actions to be taken based on this information? Are there other questions on Server Fault that cover some of these? Commandeering: This question was originally asking about running IIS and Apache on the same server, but the same concepts can be applied to any server software receiving connections from clients. The Answers below describe the technical problems and solutions of using DNS and application protocol support to assign a port number for a client to connect.

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• Is encryption really needed for having network security? [closed]

  - by Cawas

  I welcome better key-wording here, both on tags and title. I'm trying to conceive a free, open and secure network environment that would work anywhere, from big enterprises to small home networks of just 1 machine. I think since wireless Access Points are the most, if not only, true weak point of a Local Area Network (let's not consider every other security aspect of having internet) there would be basically two points to consider here: Having an open AP for anyone to use the internet through Leaving the whole LAN also open for guests to be able to easily read (only) files on it, and even a place to drop files on Considering these two aspects, once everything is done properly... What's the most secure option between having that, or having just an encrypted password-protected wifi? Of course "both" would seem "more secure". But it shouldn't actually be anything substantial. I've always had the feeling using any kind of the so called "wireless security" methods is actually a bad design. I'm talking mostly about encrypting and pass-phrasing (which are actually two different concepts), since I won't even consider hiding SSID and mac filtering. I understand it's a natural way of thinking. With cable networking nobody can access the network unless they have access to the physical cable, so you're "secure" in the physical way. In a way, encrypting is for wireless what building walls is for the cables. And giving pass-phrases would be adding a door with a key. So, what do you think?

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• Understanding encryption Keys

  - by claws

  Hello, I'm really embarrassed to ask this question but its the fact that I don't know anything about encryption. I always avoided it. I don't understand the concept of encryption keys (public key, private key, RSA key, DSA key, PGP Key, SSH key & what not) . I did encounter these in regular basis but as I said I always avoided them. Here are few instances where I encountered: Creating Account: A public RSA or DSA key will be needed for an account. Send the key along with your desired account name to [email protected] I really don't know what are RSA/DSA or How to get their keys? Do I need to register some where for that? Mailing: I'm unable to recall exactly but I've seen some mails have some attachments like signature or the mail footer will have something called PGP signature etc.. I really don't get its concept. GIT Version control: I created account in assembla.com (for private GIT repo) and it asked me to enter "SSH keys" to my profile. Where am I gonna get these? Why do I need it? Isn't SSH related to remote login (like remote desktop or telnet)? How are these two SSHs related & differ? I don't know in how many more situations I'm going to encounter these things. I'm really confused and have no clue about where to start & how to proceed to learn these things. Kindly someone point me in correct direction. Note: I've absolutely zero interested in encryption related topics. So, there is no way I'm going to read a graduate level book on this subject. I just want to clear my concepts without going into much depth.

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• Roaming Profiles & Redirected Folders - storage consumption? offline files and caching?

  - by Ben Swinburne

  I understand the concepts of both roaming profiles and folder redirection and have used both separately before. I am about to set up a network from scratch and would ideally like to use both for the following reasons primarily Roaming profiles allow users to log on to any machine and have their profile Redirected profiles allow users to have their My Documents and Desktop etc backed up without the need to log off at the end of the day. The servers can run their backups overnight and there are no missing files due to the user not logging off. Redirected profiles largely alleviate the slow log in times caused by large profiles. My question is if some of the folders are redirected and therefore not part of the roaming profile what happens on machines which truly roam (i.e. laptops)? If there's offline files or a cache does this mean that the problem whereby a user has to log off comes back? By having them both enabled, is there any duplication i.e. if I have a users$ share and a profiles$ share would I have Desktop twice for example?

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• Partitioning & Linux

  - by Zac

  Every tutorial on Linux-based partitioning schemes (or, just partitioning in general) will tell you that a PC can have either 4 primary partitions, or 3 primaries and 1 extended. They will all also tell you that Linux (in my case, Ubuntu) can be installed on either. It's also come to my attention that it is not too atypical for FHS directories, such as usr/, tmp/, etc/, home/ or var/ to be mounted separately on other partitions. Several questions I am unable to find the answers to, purely for my own edification: (1) By "PC", are we really talking about common PC disk types, like IDE or SATA? I guess I'm wondering why PC uses are limited to 4 primaries or 3 primaries + 1 extended (2) I'm choking on some basic OS concepts: it is said that a partition can be mounted by a file system or an OS. So I assume this means I can somehow instruct Ubuntu to mount to 1 partition, and then any part of, say, ReiserFS, to be mounted to another partition? How? (3)(a) What about creating swap partitions? Is there too much of a good thing with swap partitioning? If I have 4GB RAM over 320GB disk, what should my swap partition size be, and why? (3)(b) Are swap files the only way to create swap partitions? Wouldn't a Linux partitioning utility allow me to define a partition as being for virtual memory only? (4) Why are partitions limited to being "mounted" by just OSes and file systems? Why couldn't I write a program to take up its own, say, 512 MB partition, and then have it invoked or uses by an OS installed on another partition? Thanks for shedding any light here... not critical that I know this stuff, but it's got me thinking incessantly. And when I think incessantly, I...can't......sleep....

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• Asterisk dialplan context and label clarifications

  - by liv2hak

  I have been learning Asterisk dial plan for the past week.I have written down a simple IVR system with two levels of menu and an exit option.I have used concepts from different tutorials on the web.Can someone confirm if the IVR below is correct? Correct in the sense that if the below is used will it work.I know the IVR does not do much yet.But I am just trying to clarify my understanding. [incoming] exten => 123,1,Answer() same => n(menuprompt),Background(main-menu) exten => 1,1,Playback(digits/1) same => n,Goto(incoming,menuprompt,123) exten => 2,1,Playback(digits/2) same => n,Goto(incoming,menuprompt,123) exten => 9,1,Hangup() [main-menu] exten => n(menuprompt),Background(main-menu) exten => 3,1,Playback(digits/3) same => n,Goto(main-menu,menuprompt,n) exten => 4,1,Playback(digits/4) same => n,Goto(main-menu,menuprompt,n) exten => 9,1,Hangup()

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• What does "incoming" and "outgoing" traffic mean?

  - by mgibsonbr

  I've seen many resources explaining how to set up a server's firewall to allow incoming and outgoing traffic on HTTP standard ports (80 and 443), but I can't figure out why I would need either of them. Do I need to unblock both for a "regular" web site to work? For file uploads to work? Are there situations where it would be advisable to unblock one and leave the other blocked? Sorry if that's a basic question, but I couldn't find it explained anywhere (also I'm not a native english speaker). I know in a "regular" web site the client is always the one who initiates a request, so I'm assuming a web server must accept incoming traffic on those ports, and my common sense tells me the server is allowed to send a response without unblocking anything else (otherwise it wouldn't make sense to have two types of rules). Is that correct? But what is an outgoing web (service) traffic, and what would be its use? AFAIK if the server wanted to initiate a connection with another machine, the specific port that matters is the one in the other end (i.e. the destination port would be 80), on its end any free port could be used (the source port would be random). I can open HTTP requests from my server (using wget for instance) without unblocking anything. So I'm assuming my concepts of "incoming" and "outgoing" are wrong somehow.

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• Parking domains and avoiding so called "search engine penalities"

  - by senthilkumar-c

  I have purchased two domains from one particular registrar and hosting from GoDaddy. Assume they are domain1.com and domain2.com Assume my hosting IP address is 111.111.111.111 I added both domain1.com and domain2.com in my domain management control panel and gave the same two nameservers for both domains at my registrar's control panel. So, now, both domains should show the same website. When I ping "domain1.com" or "domain2.com" the results say - Pinging domain1.com [111.111.111.111] with 32 bytes of data: Pinging domain2.com [111.111.111.111] with 32 bytes of data: respectively. So, they both point to the same hosting IP. BUT, internally, I have configured IIS to point them to different folders so that different websites are shown. (My hosting plan is expensive and I intend to use the space and bandwidth for many websites). But still, technically, all domains point to same IP address. Is this a bad thing? Is this what is called "domain parking"? I read some search engine forum posts that two domains pointing to the same IP/Website will be penalised by search engines and stuff. I have also read that simply "parking" the domains won't attract penality. I don't know whether what I have done is parking or the so called "wrong" thing. Can someone shed light on what I have done and what I should do? I don't want to be blacklisted by any search engine. P.S. I know this is not a search engine forum, but I am new to website hosting and domains and I am very weak in nearly all technical terms and concepts relating to web hosting and domains. I thought this will be a good place to understand these things.

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• What is the max supported number of SATA devices (using cable adapters) on a Dell SAS 6/iR adapter?

  - by Zac B

  I've got a Dell SAS 6/iR PCI-E adapter. I don't have a multiplier backplane. I'm planning on connecting SATA (non SAS) drives. If I buy cable adapters only (ones that split a SAS connector on the card to a certain number of SATA cables), how many drives can I connect to this card? The way I see it, there are two limitations: a limitation imposed by the theoretical max number of devices supported on the card (which I've dug through the specs to find, but haven't seen yet), and a limitation imposed by the number of SAS plugs on the card multiplied by the number of SATA cables that come out of the highest-multiplying splitter I can buy. The answer to my question would be the minimum of those two limitations. I've seen 4x SATA coming out of some splitters; are there any that have more? Alternatively, if this is an RTFM question, does anyone have a good link to a "this is how SAS works, this is how you figure out the max number of devices, and this is how the concepts of 'ports', 'lanes', 'endpoint devices', and 'connectors' all relate in SAS-land" document? I've looked around on the Dell docs, but haven't found anything that explains this to someone at my level of understanding of SAN/enterprise storage technologies. Cheers!

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• Memory overcommitment on VmWare ESXi 5.0

  - by Tibor

  I would like to understand better the possibilities of VmWare ESXi memory overcommitment. I've read this paper from VmWare, so I am familiar with general concepts, such as hypervisor swapping, memory balooning and page sharing. It seems that a combination of these techniques allows for quite a large degree of overcommitment. However, I am not sure. I am deploying a virtual test lab comprising of 4 identical sets of virtual servers and workstations and a couple of virtual router instances. Overall, I expect to be running around 20 virtual machines with Windows XP, Windows 7 and Ubuntu for workstation hosts as well as CentOS and Windows 2008 Server instances for servers. The problem is, however, that the host machine only has 12GB of RAM and I don't have an option to stuff in some more. I would like to know what is the best option to configure hosts in order to achieve reasonable performance within the constrains. I have these two options: Allocate as little as possible of RAM to each virtual machine. Allocate an extraordinary amount (such as 4 GB per instance) and let the baloon driver do the rest. Something else? Which would work better? Machines will mostly be idle, so I don't have any major performance expectations, but they should run reasonably smoothly nevertheless.

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• allow spoofing when using tun

  - by Johnny

  I have a working openvpn setup with a server and a number of clients. How would i go around allowing IP spoofing through the openvpn server? (to demonstrate security concepts)? A normal ping from client to server goes through all right: root@client: hping3 10.8.0.1 HPING 10.8.0.1 (tun0 10.8.0.1): NO FLAGS are set, 40 headers + 0 data bytes len=40 ip=10.8.0.1 ttl=64 DF id=0 sport=0 flags=RA seq=0 win=0 rtt=124.7 ms root@server:/etc/openvpn# tcpdump -n -i tun0 tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on tun0, link-type RAW (Raw IP), capture size 65535 bytes 10:17:51.734167 IP 10.8.0.6.2146 > 10.8.0.1.0: Flags [], win 512, length 0 But when spoofing a packet, it does not arrive at the openvpn server: root@client: hping3 -a 10.0.8.120 10.8.0.1 HPING 10.8.0.1 (tun0 10.8.0.1): NO FLAGS are set, 40 headers + 0 data bytes root@server:/etc/openvpn# tcpdump -n -i tun0 tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on tun0, link-type RAW (Raw IP), capture size 65535 bytes My current config files server.conf local X.Y.Z.P port 80 proto tcp dev tun ca ca.crt cert server.crt key server.key # This file should be kept secret dh dh1024.pem server 10.8.0.0 255.255.255.0 push "redirect-gateway def1 bypass-dhcp" keepalive 10 120 comp-lzo persist-key persist-tun persist-local-ip status openvpn-status.log verb 3 client.conf client dev tun proto tcp remote MYHOST..amazonaws.com 80 resolv-retry infinite nobind persist-key persist-tun ca ca.crt cert client.crt key client.key ns-cert-type server comp-lzo verb 3

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• ASA access lists and Egress Filtering

  - by Nate

  Hello. I'm trying to learn how to use a cisco ASA firewall, and I don't really know what I'm doing. I'm trying to set up some egress filtering, with the goal of allowing only the minimal amount of traffic out of the network, even if it originated from within the inside interface. In other words, I'm trying to set up dmz_in and inside_in ACLs as if the inside interface is not too trustworthy. I haven't fully grasped all the concepts yet, so I have a few issues. Assume that we're working with three interfaces: inside, outside, and DMZ. Let's say I have a server (X.Y.Z.1) that has to respond to PING, HTTP, SSH, FTP, MySQL, and SMTP. My ACL looks something like this: access-list outside_in extended permit icmp any host X.Y.Z.1 echo-reply access-list outside_in extended permit tcp any host X.Y.Z.1 eq www access-list outside_in extended permit tcp any host X.Y.Z.1 eq ssh access-list outside_in extended permit tcp any host X.Y.Z.1 eq ftp access-list outside_in extended permit tcp any host X.Y.Z.1 eq ftp-data established access-list outside_in extended permit tcp any host X.Y.Z.1 eq 3306 access-list outside_in extended permit tcp any host X.Y.Z.1 eq smtp and I apply it like this: access-group outside_in in interface outside My question is, what can I do for egress filtering? I want to only allow the minimal amount of traffic out. Do I just "reverse" the rules (i.e. the smtp rule becomes access-list inside_out extended permit tcp host X.Y.Z.1 any eq smtp ) and call it a day, or can I further cull my options? What can I safely block? Furthermore, when doing egress filtering, is it enough to apply "inverted" rules to the outside interface, or should I also look into making dmz_in and inside_in acls? I've heard the term "egress filtering" thrown around a lot, but I don't really know what I'm doing. Any pointers towards good resources and reading would also be helpful, most of the ones I've found presume that I know a lot more than I do.

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• Performance-optimizing Oracle 10g on a server that is also a Tomcat JSP app server?

  - by PKHunter

  I have inherited a simple RedHat 5 - 64bit platform. It has SCSI disks on RAID1, with 16GB of RAM. Double Core CPU. Oracle 10g, Release 2. This would be a decent platform for running the DB only, perhaps, but the same server in an "A-A mode" clustering (very simple) also runs Tomcat and there are several Java servlets running on this. Sadly there is no caching platform etc. We only use an external CDN for some html caching. I am personally more familiar with web environments on the LAMPP platform (apache, php, mysql, postgresql). PROBLEM: Because the server has both Tomcat JSP/Java and Oracle 10g running on the same server, with no caching, I have some issues of the server going down. Often, sadly. QUESTION: What are my options in terms of improving performance of all these different apps? Connection Pooling? Example, in Postgresql world we have PgBouncer, which really helps things. Does Oracle have something similar? Or is there a famous Java-based external pooler that people use in production environments? (I'm not familiar with Java) Any "SQL cache" as in the MySQL and Postgresql world? Any other kind of application cache, as "APC" or "eAccelarator" in the PHP world? The "OSCache" stuff from the Java world (JSP thingie I found on Google: http://onjava.com/pub/a/onjava/2005/01/05/jspcache.html?page=2) ... What else? Sorry if this is a noob question. I have googled and googled, but problem is I don't know what to google for, other than the broad general concepts above. So if not full answers, I would even appreciate basic pointers and I am happy to JFGI myself. Thanks!

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• OS choice between: Debian, gNewSense, and OpenSolaris

  - by penyuan

  I am planning to migrate from Mac OS X and Windows to either a Unix or Linux distribution, i.e. I am a Linux/Unix beginner. Right now the following caught my interest: Debian: Well established with huge repository of 20000+ apps. gNewSence: "Totally free" version of Ubuntu, so it should be more beginner friendly? OpenSolaris: Also open-source, and built on "strong" Unix base. I do mainly basic tasks such as web browsing, office work, maintaining big photo collection, and a little bit of programming. Questions: How "free" are each of these distributions compared to each other, is this whole freedom thing a big deal? Will a binary labeled as for Ubuntu work on gNewSense? What are simple IDEs for Debian and gNewSense?

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• rename file names from lower case to upper case

  - by Adnan

  Hello, I have about 2k of file that are currently in lower case like: file_one.cfr file_two.cfr .... I am searching for a fast way to rename them to upper case so they would be like; FILE_ONE.cfr FILE_TWO.cfr .... If I use from my shell; for i in *; do mv $i `echo $i | tr [:lower:] [:upper:]`; done I can get all file and the file extensions to upper case. But the extension should remain in lowercase, so my approach does not work. Any programming language is welcome.

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