udp

Discovering maximum packet size

I'm working on a network-related project and I am using DTLS (TLS/UDP) to secure communications. Reading the specifications for DTLS, I've noted that DTLS requires the DF flag (Don't Fragment) to be set. On my local network if I try to send a message bigger than 1500 bytes, nothing is sent. That makes perfect sense. On Windows the send...

Interview Questions that can be asked on TCP/IP, UDP, Socket Programming ?

I am going for an interview day after tomorrow where i will be asked vaious questions related to TCP/IP and UDP. As of now i have prepared theoritical knowledge about it. But now I am looking up for gaining some practicle knowledge related to how it works in a network. What all is going in vaious .NET classes. I want to create a very sm...

Why do I get UDP datagrams out of order even with processes runnning locally?

Well, I'm developing a java interface between a streaming server and a flash client. I noticed that UDP datagrams can reach my interface out of order even if both processes are running locally. Is that normal? I thought that as no datagram has to go through any router or any network device, then that should not be happening. Thanks in ...

can I read exactly one UDP packet off a socket?

Using UNIX socket APIs on Linux, is there any way to guarantee that I read one UDP packet, and only one UDP packet? I'm currently reading packets off a non-blocking socket using recvmsg, with a buffer size a little larger than the MTU of our internal network. This should ensure that I can always receive the full UDP packet, but I'm not s...

UDP receiver with background threads

Hi, I am writing a UDP receiver using UdpClient class. IPEndPoint broadcastAddress = new IPEndPoint(IPAddress.Any, Settings.Default.SenderPort); UdpClient udpClient = new UdpClient(); udpClient.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReceiveBuffer, 102400); udpClient.Client.SetSocketOption(SocketOptionLevel.So...

how to customize the filter when following a stream in wireshark?

when selecting a packet and choosing to follow the stream, wireshark automatically sets a filter that looks something like this: (ip.addr eq 10.2.3.8 and ip.addr eq 10.2.255.255) and (udp.port eq 999 and udp.port eq 899). i'd like to be able to set that myself when following the stream, but have not been able to identify where to do that...

How to do UDP without port forwarding

Hi all, I am creating an application in C#, It should send data with UDP. Everything works fine until, I try to communicate with a PC that is on the internet behind a router. How do I fix this so that I can use UDP without port forwarding? ...

UDP Socket Client in .NET

I use UDP Sokckts in my client application. Here are some code snippets: SendIP = new IPEndPoint(IPAddress.Parse(IP), port); ReceiveIP = (EndPoint)(new IPEndPoint(IPAddress.Any, 0)); socket = new Socket( AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp); socket.Bind(ReceiveIP); And to Receive (while(true)): ...

Does it make sense to have more than one UDP Datagram socket on standby? Are "simultaneous" packets dropped or queued by the kernel?

I'm coding a networking application on Android. I'm thinking of having a single UDP port and Datagram socket that receives all the datagrams that are sent to it and then have different processing queues for these messages. I'm doubting if I should have a second or third UDP socket on standby. Some messages will be very short (100bytes ...

Giving Users an Option Between UDP & TCP?

After studying TCP/UDP difference all week, I just can't decide which to use. I have to send a large amount of constant sensor data, while at the same time sending important data that can't be lost. This made a perfect split for me to use both, then I read a paper (http://www.isoc.org/INET97/proceedings/F3/F3_1.HTM) that says using both...

Python socket error on UDP data receive. (10054)

I currently have a problem using UDP and Python socket module. We have a server and clients. The problem occurs when we send data to a user. It's possible that user may have closed their connection to the server through a client crash, disconnect by ISP, or some other improper method. As such, it is possible to send data to a closed sock...

C++ Winsock non-blocking/async UDP socket

Hi all! I'm developping a little data processor in c++ over UDP sockets, and have a thread (just one, and apart the sockets) that process the info received from them. My problem happens when i need to receive info from multiple clients in the socket at the same time. How could i do something like: Socket foo; /* init socket vars and ...

[Android] SocketException (The system call was cancelled)

Hi. I am working on a android project and I need to connect the gPhone with the PC using UDP socket. The same operation, sending a message to from gPhone to the PC, returns different results in different time: Sometimes succeeded and sometimes throws a SocketExcepton(The system call was cancelled). Can anyone tell me what possibly result...

What's a good way to detect wrap-around in a fixed-width message counter?

I'm writing a client application to communicate with a server program via UDP. The client periodically makes requests for data and needs to use the most recent server response. The request message has a 16-bit unsigned counter field that is echoed by the server so I can pair requests with server responses. Since it's UDP, I have to ha...

No network packets sent immediately after quick physical disconnect and reconnect.

I am using Boost's ASIO libraries to establish a UDP connection to a remote server. To make sure the connection is active, every second a keep-alive message is sent to the server. I have noticed that if I unplug the network cable and reinsert it quickly, the first 2 or 3 keep-alive messages after the reinsert are never sent. I tested t...

How to recover gracefully from a C# udp socket exception

Context: I'm porting a linux perl app to C#, the server listens on a udp port and maintains multiple concurrent dialogs with remote clients via a single udp socket. During testing, I send out high volumes of packets to the udp server, randomly restarting the clients to observe the server registering the new connections. The problem is th...

How to distinguish between two different UDP clients on the same IP address?

I'm writing a UDP server, which is a first for me; I've only done a bit of TCP communications. And I'm having trouble figuring out exactly how to distinguish which user is which, since UDP deals only with packets rather than connections and I therefore cannot tell exactly who I'm communicating with. Here is pseudocode of my current serv...

Java Server Client Program I/O Exception

I made this program: http://java.sun.com/docs/books/tutorial/networking/sockets/clientServer.html And it works perfectly if I put the server's hostname as 127.0.0.1 or my computers name (Ajay-PC). However these 2 methods are LAN or local only not internet. So I changed it to my internet ip. 70.128.xxx.xxx etc. But it didn't work. I ch...

Receiving broadcast packets using packet socket

Hello I try to send DHCP RENEW packets to the network and receive the responses. I broadcast the packet and I can see that it's successfully sent using Wireshark. But I have difficulties receiving the responses.I use packet sockets to catch the packets. I can see that there are responses to my RENEW packet using Wireshark, but my functi...

Enhance UDP - Windows Mobile 6

Hello, I am currently working on a VOIP system for WM6 devices in C#. Recording and playback speach is noproblem but with the transmission, my signal gets distorted. How can i solve these distortions. RTP would be a solution but i can't find any suitable ways to implements RTP/SID... Thanks in advance Gerrit ...