networking

Problem with CFRunLoopRun();

Hello, I have a problem I created this client connects to a server and then want to send and receive strings (this is not implemented yet). When creating the connection I have a problem since the creation of the connection does not do "CFRunLoopRun ();"( tested by degbug). Someone any idea? Thank you. - (void) acceptConnection:(int)fd {...

Weird send() problem (with Wireshark log)

I had another question about this issue, but I didn't ask properly, so here I go again! I'm sending a file by sending it in chunks. Right now, I'm playing around with different numbers for the size of that chunk, to see what size is the most efficient. When testing on the localhost, any chunk size seems to work fine. But when I tested ...

Sources of latency in sending-receiving tcp/udp packets in linux

Hello What are sources of latency in process of sending/receiving tcp/udp packets in linux 2.6 ? I want to know a latency sources in "ping-pong" latency tests. There are some rather good papers of ethernet latency, but they cover only latency sources in the wire and switch (and rather cursory, only for specific switch). What steps of...

data path (travel) of tcp data from "write" syscall downto I/O registers programming

Hello Is there a good overview of tcp data path in Linux (2.6, not 2.4 if the path actually differ)? Where is a packet on different stages of tcp/ip stack handling? How packet is packed to tcp segment, then ip packet. How it is transmitted to network card? (with series of I/O regs write and DMA?) Is it transmitted to network card in th...

Sending an int array through Winsocks

I'm trying to send an int array through Winsocks. I might be wrong, but I'm pretty sure only a char* is supported so I'm kind of stuck on how to do this properly. There are also problems with little/big edian, so what would be a good way to do this? I've already asked a question of converting int array to char but it was recommended to s...

How to send and receive file on Silverlight application?

Hi. I am writting Silverlight client-server application. Server part is WinForm application an client part is Silverlight. I use TCP connction. I use sockets for sending and receiving information. But now I need to send a file, size of which may be greater then 1 Mb, so I can't use socets to send that file as bite stream. I wont to send ...

How can I enable/disable network connection options programmatically

When I open the properties on a network connnection on windows, I see this dialog: In this dialog, in the check-listbox I can enable or disable options like "File or printer sharing", "client for microsoft networks" or network filter drivers. My question is: How can I enable/disable these options programatically? I didn't find anythin...

Identify machines behind a router uniquely based on ipaddress

Some background first. I have a .net client agent installed on each of the machines in the lan. They are interacting with my central server [website] also on the same lan. It is important for my website to figure out which of the machines can talk to each other. For example, machines of one subnet cannot directly talk to machines of ano...

How to change subnet mask and DHCP enabled flag in C++ and Windows XP

Does anyone know how to change the subnet mask and the DHCP enabled flag on Windows XP / Vista / 7 from a C++ program? The Windows API has a GetAdaptersInfo() routine which will give you that information, but I need the counterpart SetAdaptersInfo() which doesn't seem to exist. I've looked all over MSDN and the web and don't see how to...

What was the motivation for adding the IPV6_V6ONLY flag?

In IPv6 networking, the IPV6_V6ONLY flag is used to ensure that a socket will only use IPv6, and in particular that IPv4-to-IPv6 mapping won't be used for that socket. On many OS's, the IPV6_V6ONLY is not set by default, but on some OS's (e.g. Windows 7), it is set by default. My question is: What was the motivation for introducing th...

How to access a web service behind a NAT?

We have a product we are deploying to some small businesses. It is basically a RESTful API over SSL using Tomcat. This is installed on the server in the small business and is accessed via an iPhone or other device portable device. So, the devices connecting to the server could come from any number of IP addresses. The problem comes wit...

Check if the internet cannot be accessed in Python

I have an app that makes a HTTP GET request to a particular URL on the internet. But when the network is down (say, no public wifi - or my ISP is down, or some such thing), I get the following traceback at urllib2.urlopen: 70, in get u = urllib2.urlopen(req) File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/url...

Matching an IP address with an IP range?

I have a MySQL table setup as follows: +---------------+-------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +---------------+-------------+------+-----+---------+----------------+ | ipaddress_s | varchar(15) | YES | MUL | NULL | | | ipaddres...

Add a banner at the top on unknown HTML page on the fly; Send a note to network user

I want to be able to send messages to users of network that my computer routes to. Modifying requested pages, by adding messages like Warning: this access point is going down soon" or Network quota exhausted or You are overusing the network connection and may be banned or Security notice: this is unencrypted netwo...

one two-directed tcp socket OR two one-directed? (linux, high volume, low latency)

Hello I need to send (interchange) a high volume of data periodically with the lowest possible latency between 2 machines. The network is rather fast (e.g. 1Gbit or even 2G+). Os is linux. Is it be faster with using 1 tcp socket (for send and recv) or with using 2 uni-directed tcp sockets? The test for this task is very like NetPIPE ne...

Serving web application without Lighttpd/Apache

Hi, As Rails applications default run on port 3000, would it be possible to start the application on port 80? Is it really required to have a fastcgi/mod_proxy enabled web server in front? My users won't be more than three at a time. If so, how would I be able to do so? Thanks! ...

problem with kCFSocketReadCallBack

Hello. I have a problem with my program. I created a socket with "kCFSocketReadCallBack. My intention was to call the "acceptCallback" only when it receives a string to the socket. Instead my program does not just accept the connection always goes into "startReceive" stop doing so and sometimes crash the program. Can anybody help? Thanks...

c# peer-to-peer networking - getting around routers

I want to code a peer-to-peer like chat program in C#. I am trying to figure out how the networking would work. I know that the concept is that each peer is a client and a server at the same time. It can connect and be connected to. But my question is, how do you connect to a computer behind a router without the port being forwarded to t...

GAE and Socket Data

I have a field device which keeps on sending data over to any designated port using sockets. I am planning to use GAE for server-side infrastructure. I read GAE does not support sockets. But i can configure the device to send the data over port 80. so we wrote a genericservlet to capture this data on GAE. But it is not obtaining any va...

Unit Testing a Java Chat Application

I have developed a basic Chat application in Java. It consists of a server and multiple client. The server continually monitors for incoming messages and broadcasts them to all the clients. The client is made up of a Swing GUI with a text area (for messages sent by the server and other clients), a text field (to send Text messages) and a...