UDP stands for User Datagram Protocol. With UDP applications can send messages (datagrams) to other hosts on a network without requiring prior communications to set up special transmission channels or data paths.

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What is the reason for speed jumps in this Wifi transmission?

In this picture: The X axis is time slots of 5 seconds each and the Y axis is the number of 1KiB packets transmitted in that slot. The blue graph shows the actual number of transmitted packets ...
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100 views

Unable to see broadcast packets with tcpdump

I am launching an application which broadcasts udp packets. I also have a simple python script to confirm that these packets are being broadcast: sock = socket.socket(socket.AF_INET, socket....
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387 views

How to experience UDP hole punching using Ncat under Linux?

I'd like to see UDP hole punching in action. I tested it under Linux, using Ncat. Here's what I tried: Open port 1234/UDP on host A and port 12345/UDP on host B's firewall (I'm still behind NAT, but ...
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What is the difference between UDP and HTTP torrent trackers?

In the context of bittorrent what's the difference between http and udp trackers? HTTP is an application layer protocol and UDP is a transport layer protocol so the concepts seem non-overlapping. I ...
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233 views

Emulate console by sending data on one UDP port, and receive text from another

I'm trying to establish a “console-like” connection with a National Instruments cRIO-FRC. It broadcasts its console output onto 255.255.255.255, UDP port 6666. I can listen to it with: socat UDP-...
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200 views

How to optimise a Motorola Wing 5.3 Access Point for UDP traffic

I have a motorola wing v 5.3 which I need to optmise for UDP traffic. I have some UDP packet loss and I think that if I change the AP configuration I would get a better result. Anyone has experience ...
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294 views

Is it possible to edit TCP and UDP packets?

Is it possible to edit the UDP and TCP packets a program sends? For example, we have a program that sends some information to its server. But we don't want to send some information that might be ...
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568 views

Dropbox LAN sync - hint for an IP address

In my work network UDP broadcast networks are isolated between the WiFi and wired channels, so LAN sync discovery does not work. Is there a way to explicitly tell Dropbox to try a specific IP address ...
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349 views

Tunnelling TCP connection through NAT

My server is in my school's NAT and my desktop computer is in my home NAT. I want to SSH to my server from home. I normally used school's VPN, but recently for some reason I can't. So I'm looking for ...
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486 views

Can I get UDP Hole Punching with (any) VNC client to get around the local firewall/router?

I don't have access to the local internet router, so I'm unable to setup port forwarding on my lan connection. I'm just trying to find out if there is any way for me to get around my local router ...
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226 views

in wireshark how to know if packet was send to vpn or to internet?

Thanks to my previous question when vpn is connected intenet is not accessible I have configured VPN connection so I can use internet at the same time. Right now I write this post and I'm connected to ...
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236 views

Mounting an NFS share with udp or mntudp options

According to the documentation of NFS client on Mac OS X 10.7 user can specify following options: udp Use UDP transport protocol. and mntudp Force the mount protocol to use UDP transport, ...
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56 views

Why is there no UDP port forwarding in SSH?

I know SSH can forward TCP ports, not UDP. I'm not seeking help to circumvent this restriction (this subject is covered here). I'd like to know what is the reason SSH never got UDP forwarding ability....
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50 views

What is a simple STUN test I can perform from a Windows machine?

I want to test whether someone else's Windows machine can access a public STUN service using UDP and receive a response on its network, which I expect is behind a NAT and firewall. I do not have ...
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27 views

NTP not getting through even to DMZ

My home router seems to be blocking UDP 123. sudo ntpdate -u time.apple.com works as expected, but sudo ntpdate time.apple.com I get: "no server suitable for synchronization found" I can get a ...
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35 views

unknown local address in TCPView

I'm looking at connections in TCPView, and I'm seeing "red5" in the "local address" column. This doesn't appear to match any computers on my local network, the names of which I have seen from time to ...
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7 views

Route only on output chain?

I have two machines A and B. I want to send iperf traffic from A to B, but first have it route through a userspace program on A. I did this with a tunneling device: therefore, I used the command ip ...
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177 views

Forward all TCP and UDP connections over VPN

I have the following setup: OS: Ubuntu v13 Software: PPTP NIC 1 (eth1) IP: 10.2.95.207/24 Gateway: 10.2.95.1 (this is the network I want to connect to) NIC 2 (eth2) IP: 7.82.176.254/8 (the network ...
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122 views

OpenVPN sans port forwarding on unfriendly networks

I have a problem. I'm about to move onto campus right in the middle of the semester. For a student, I have a complicated network setup where all of my systems are reliant on NAS and all of them VPN ...
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350 views

Home router config to allow for UDP broadcast

I have a homegrown piece of software that "listens" to UDP traffic at 255.255.255.255:5010. It works just great on my home network, but does not work on other people's networks. I think that my ...
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695 views

Re-stream (forward) UDP-Live-Video-Stream (using winsock) reduce video quality?

So, I used ffmpeg to stream the live webcam using UDP protocol to port 1111 : ffmpeg -f dshow -i video="Lenovo EasyCamera" -f mpegts udp://localhost:1111 When I played it directly by ffplay from ...
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2k views

udp client sending ICMP “port unreachable” when receiveing messages from the server

(Note: I moved this question from StackOverflow, because it's to be considered off-topic there, better fits here, and still unsolved) I have a udp client using luasocket, basically doing this (with a ...
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783 views

“udp relay” via openssh socks proxy

I'm trying to run a UDP based multiplayer game (dota 2) via the following chain dota2 (OS X)-> proxycap -> ssh tunnel -> home machine (OS X) -> internet The home machine is running the ...
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2k views

FFmpeg/avconv and UDP - connect listener after sender?

I'm trying to troubleshoot a port binding issue in avconv/FFmpeg. I have two test commands; one which sends an audio stream over UDP: avconv -i test.wav "udp://localhost:6613?localport=6614&reuse=...
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316 views

Artificial network delay tcp/udp (bigger ping) for defined application? (windows)

I have a game where people can easy detect who i am looking at my ping, i want to make my ping highter. How can i set network delay for all network connections for defined application?
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724 views

What is blocking incoming packets to port 67?

I have a DSP connected to a Windows 7 laptop by Ethernet. The laptop has all firewalls disabled (I’ve even tried stopping the Windows firewall service and DHCP). The DSP is sending well-formed BOOTP ...
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57 views

UDP Short packet

My mychine is probably under some kind of DoS attack, my syslog is full of: kernel: [5618300.661196] UDP: short packet: From 119.37.12.102:53 4103/1480 to x.9.158.119:3604 kernel: [5618300.663014] ...
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15 views

UDP fails horribly after waking from sleep (and maybe without sleep too)

We've got a PC running Windows 7 Home Premium that fails in a rather odd way after waking from sleep (and possibly other times as well, we haven't been keeping detailed records). The most obvious ...
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13 views

Sending ihex file over UDP using sockets

I am working with IPv6 and UDP sockets using python-2.7. I am particularly focusing on IPv6 Multicasting ff02::1 where every Link-Local address device (with fe80::) responds to queries from a central ...
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16 views

UDP Forwarding redirection keeping source info in Linux

I would like to do an UDP Forwarding redirection of traffic in machine B, so UDP traffic from machine A would go to machine C. I have used iptables and that goes fine. The problem I have is that I'm ...
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31 views

TCP and UDP do not work with firewall

I can not connect my TCP-Client to my TCP-Server. Here is my Code: http://stackoverflow.com/questions/35661591/tcp-server-does-not-work-with-firewall I have already opened my TCP-Port "8888" in the ...
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44 views

UDP port 9987 wont open on my firewall

I have a zywall-usg-200 and i have tried to open ports, i managed to open two TCP ports but the UDP port 9987 fails, cant connect to it. Does anyone have the same problem? Or is it just my firewall
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61 views

Why do UDP Packets stop being sent if TTL Expire message received?

I have a program that sends UDP packets to devices as part of a task. If during this task, any of the targeted IP addresses causes a TTL Expired packet to be received, the program can no longer get ...
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187 views

How to stream video by using UDP VLC player?

I am trying to stream the video and this is what I did. start C:\Progra~2\VideoLAN\VLC\vlc udp://@:60000 start C:\Progra~2\VideoLAN\VLC\vlc.exe C:\Progra~2\VideoLAN\VLC\FullDuplexRadio.3gp --sout=#...
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26 views

Looping back network traffic on the same machine

I have some 3rd party software that expects UDP traffic to/from other machines on the same UDP port. I want two instances to run on the same machine and talk to each other. I'm running it in Windows7....
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17 views

Multiple UDP servers at same port, only locally?

Someone sends a UDP packet over the internet to a router public IP and port. Can this packet reach all the PCs of the LAN (using broadcast?) if they are listening on the port for UDP ?
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24 views

simulation gets disconnected from adhoc network when working with UPD blocks

I'm working with MATLAB simulink and trying to send data using UDP block from a model running on external mode (on a quad-copter which runs on linux ) to a model running in normal mode on my computer ...
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80 views

Broadcasting with socat via UDP, timeouts (maybe package lost?)

I want to setup a small broadcaster. I capture the stream from a program via UDP and broadcast it through the network (from IP *2 to *32, because just maximum 32 devices are connected). If I give ...
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174 views

UDP traffic through OpenVPN tunnel

I want to tunnel UDP traffic (Video) through OpenVPN between two clients. I am able to ping both the clients but unable to transmit video through the tunnel to the Client B.
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107 views

UDP traceroute delay?

We are seeing timeout packages when running traceroute command between two Linux systems on a private network. However, we do not see such symptoms using TCP or ICMP over traceroute. This is a private ...
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48 views

How to create a wireless-to-ethernet router?

I have a Debian machine, which I want to turn into a router. It will connect via wireless to a access-point, where it will get an IP. To its ethernet port, other machines will be connected. It will ...
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464 views

UDP port binding to loopback interface

I've been trying to play a video game in multiplayer, but after trying a lot of time, I begun to realize there was some problem with my loopback interface (Windows 7) I have UPnP activated in my ...
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492 views

How to use netperf on specific NIC port?

I have two servers, SERVER and CLIENT and each server has its own onboard 1 GbE ports, and its own NIC with a 10 GbE port. SERVER and CLIENT are interconnected on both a 1 GbE switch (administrative ...
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68 views

UDP causing problems with other connections

I have implemented a file transfer program on Windows 64-bit platform using winsock API. I am using a 1Gbps connection. When I transfer files using TCP protocol, I am getting only 320 Mbps. when I ...
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221 views

Send data from file to local UDP port

I've got an application, A, that listens on a user-defined UDP port for a specific message that normally comes from another application, B. Application B has a tool that allows recording these ...
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2k views

How to direct a UDP Packet through a vps tunnel?

How to direct a UDP Packet through a VPN Tunnel over a WAN? Have been trying to set up a instant messenger service though the office network and it dose not have UDP flooding or UDP broadcasting. ...
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244 views

UDP NAT punching for linksys wrt54g

I could not explain the strange NAT behavior, hope someone could help: I have a linksys wrt54g router at home. Client sends UDP keep alive packet from 192.168.1.20:16688 (nat outside public IP/port ...
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483 views

What would cause different rates of packet loss between client and server in UDP?

If I've implemented a reliable UDP file transfer protocol and I have a file that deliberately drops a percentage of packets when I transmit, why would it be more evident that transmission time ...
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4k views

RTP input stream on VLC

I'm trying to play on VLC a RTP input stream coming from the port 9954, UDP socket. So, I launch VLC on the console with this command: vlc -vvv rtp://:@9954. VLC appears, but no media is played. The ...
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115 views

windows xp irregularly refuses to connect to one specific webserver

I think of myself as an advanced user but this problem is driving me batty. Windows XP (32bit Home) going through a WRT54G router, once or twice a day at completely different random times, refuses to ...