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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Is ICMP port unreachable error generated by both TCP and UDP? [closed]

A program on machine X attempts to open a UDP connection to port 5376 on a machine Y, and a TCP connection to port 8632 on machine Z. However, there are no applications listening at the corresponding ...
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3k views

UDP blocked by Windows XP Firewall when sending to local machine

I work for a software development company but the issue doesn't seem to be programming-related. Here is my setup: Windows XP Professional with Service Pack 3, all updated Program that sends UDP ...
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19 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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11 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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1answer
7k views

Play UDP stream in VLC?

I receive an UDP video stream of which I know both the IP adresses and the incoming and outgoing ports of both computers. How can I plat his in vlc? udp:@:1234 Doesnt work for me. How to fix this?
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Does it matter what UDP port a WOL signal is sent to?

i have seen many WOL instances use port 7 and many use port 9, does it matter? Isn't it just looking for a WOL packet at layer 2 or ethernet?
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2answers
247 views

DNS Resolver for Windows over TCP

I know that DNS uses UDP with Port 53 for DNS queries. However, at my place sometimes UDP requests are blocked and DNS fails. I know that there is protocol for DNS over TCP and many public DNS servers ...
3
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1answer
53 views

UDP “connections” rejection

I'm managing (edit: is hosted by VPS hoster) small machine for couple of game servers and website server (apache) together with some friends. Problem is firewall sometimes drops UDP packets. The ...
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1answer
19 views

Read UDP packages created by another computer

Laptop 1 Laptop2 192.168.1.103 192.168.1.120 Ubuntu Windows 8 ? <-- Matlab: UDP I use MATLAB software on my windows and I ask it to generate real ...
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11 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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28 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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78 views

Understanding “cat proc/net/udp”

# cat /proc/net/udp | egrep "sl|3ADBFE0A" sl local_address rem_address st tx_queue rx_queue tr tm->when retrnsmt uid timeout inode ref pointer drops 16: 3ADBFE0A:007B ...
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1answer
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WiFi UDP unicast vs. multicast speed

From what I have gathered UDP multicast / broadcast over WiFi will not yield the speed as one would have thought. What about UDP unicast over WiFi? Can anyone confirm that the latter will have a ...
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1answer
50 views

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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1answer
22 views

Capture only UDP traffic that cannot be identified as another protocol

I have applied the udp filter in order to just capture UDP traffic, as described in Wireshark Wiki: Show only the UDP based traffic: udp However, this does not only show UDP traffic. It shows ...
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3answers
17k views

How to generate UDP packet

I want to generate UDP packet to test a program, something equivalent to using telnet to test TCP port (Can telnet generate UDP packet?) How can I do this?
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92 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 ...
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18 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 ...
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28 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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3answers
6k views

Proxifier that supports UDP?

Im looking for a proxifier that forces all Windows traffic through a specific proxy. I have my own server so I can ultimately configure any type of proxy (Socks, HTTPS, etc) so thats not a problem, ...
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13 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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16 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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35 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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2answers
10k views

Linux built-in or open source program to join multicast group?

I'm using tcpdump to capture multicast packets and had to code up a custom program to join multicast feeds so tcpdump will "see" the packets. Just wondering if netcat or any other applications can ...
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6answers
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UDP traffic through SSH tunnel

The title pretty much sums it up. I would like to send UDP traffic through a SSH tunnel. Specifically, I need to be able to send UDP packets through the tunnel and have the server be able to send ...
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1answer
98 views

Why ping/latency lower in-game than command prompt?

Is it weird that when i tested my ping to a specific gaming server on cmd, and it showed a constant and stable 42 ms (never below that), and When i played on that server in the game, it showed my ping ...
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1answer
558 views

OpenVPN working with TCP not with UDP

I have successfully set up an OpenVPN server on Debian (raspberry pi model b+). With the protocol set to TCP it works exactly as desired (internet routed through VPN, access to local network ...
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1answer
94 views

Detect RIPv1 via NMAP

Due to the recent increase of reflection attacks noted by Akamais security teams using original RIP(classful, depreciated) I'm interested to see if some of the CPE running within a network segment ...
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1answer
209 views

COD4 Linux game server doesn't send UDP packets as response to broadcast

I am setting up a bunch of Game servers for a medium sized LAN tournament using CentOS 6 and the various Linux binaries used for the game servers. With COD4 the servers did not show up in the server ...
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Is it possible to process millions of datagrams per second with Windows?

I am investigating if I can implement an HPC app on Windows that receives small UDP multicast datagrams (mostly 100-400 Bytes) at a high rate, using a dozen or up to maybe 200 multicast groups (i.e. ...
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6 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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80 views

iptables block access to all ports except 53 (tcp,udp) from one IP address

how can i block all ports from one IP address except the port 53 TCP,UDP? example: ip 192.168.0.15 access only port 53 (udp,tcp). thank you.
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297 views

How to tunnel UDP traffic over Tor?

I know that Tor does not support UDP for now . But I came upon certain application Onion Cat .But I don't know if it work or not . Is there any other procedure ? Is that even possible ? Please guide ...
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Kill UDP port that has no process?

My VPN client sometimes can't bind to the UDP port (500) it uses. It seems to leave behind a "bind" to port 500 on a previous run, even though it has quit. The port is reported as "already in ...
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1answer
63 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, ...
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118 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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1answer
191 views

ISP Issues - TCP Out-of-Order

Accessing any webpage (basically any TCP connection), results in multiple retries before and long loading times before it loads a page with missing elements (reload might fix it). Google Chrome throws ...
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116 views

UDP over Internet

I have a small problem: I want to program a simple Apllication that sends a small word (in this case: "Hello") to a server. This Server should display it via cout. This is just a project to learn how ...
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190 views

Can't connect to udp tracker (Rtorrent)

So I just got rtorrent, fixed my settings, but it still won't connect to udp no matter which torrent i use, udp is enabled and every settings seems fine. Still I can't connect! Reply if you need some ...
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3answers
8k views

How to detect if network is dropping UDP packets?

I'm got a video streaming application that runs fine in my office but fails miserably at the customer location. The symptom is that every couple of seconds, I stop receiving UDP packets for 2 seconds, ...
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82 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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183 views

sshuttle using tproxy error requires recvmsg function

I'm using sshuttle from this repo https://github.com/seanzxx/sshuttle because im using OSX Yosemite. (Original version from apenwarr not working with OSX Yosemite). it's working fine with this ...
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1answer
547 views

Why filtering on udp port in TCPDUMP gives only fragmented IP frames

I've a device capturing traffic with Tcpdump filtering on "upd dst port" then it creates a pcap file to be read in wireshark. what I obtain from running: tcpdump udp dst port 5201 -qUns 0 -i wlan0 ...
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193 views

What is the primary function of the transport layer in the Internet protocol networking code [closed]

I am not sure if I have answered this question right, so would appreciate it if someone could correct me. The question is: What is the primary function of the transport layer in the Internet protocol ...
3
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2answers
2k views

How do I control the streaming frame rate of ffmpeg?

I am using ffmpeg to stream video: ffmpeg -i $file -f mpegts udp://hostname:port On another machine, I am using VLC to play the output stream. The problem I have is that VLC is playing the stream ...
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0answers
131 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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50 views

Do I need to join a multicast group to send a packet or joining is just for listening?

I am confused here. Can anyone just send a packet to a multicast address and port? Where does the multicast group come into play here? Do I also need to send to a group? Can someone explain that to ...
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1answer
315 views

utorrent connectivity: Router drops packets

I have some problems downloading via uTorrent 3.4.2 on Win 7 x64. Symptoms: DHT is either Waiting to log in or Nodes (0), under Trackers its status is Waiting for announce... For any torrent, all ...
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2answers
2k views

Testing a Firewall against outgoing UDP ports

I'm trying to test which outgoing ports are allowed through a firewall. At the moment I can do this for TCP by port scanning portquiz.net (which is a server with all TCP ports open) from inside ...
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108 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 ...