Questions tagged [udp]
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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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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What does SSH use UDP for?
Wile doing research I noticed that SSH both uses TCP and UDP. I completely understand the use of TCP, but UDP seems a bit strange. Why would I use an "unreliable" transport protocol with minimal ...
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Why is it bad to have open ports?
Here's something that has always baffled me. Why is it bad to have open ports on your computer? Assuming you don't have a virus on your computer or some other program listening to a port that may ...
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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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what is type of ICMP packets? TCP or UDP
The ping packet is a type of ICMP packet. Is there any relation between ICMP with TCP? In other words, can we guarantee their arrival in the network?
I want to know if ICMP packets in the network are ...
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How to use UDP hole punching for a SSH tunnel / session
I want to deploy a Raspberry Pi in my weekend cottage. The Raspberry Pi is there to log the temperatures and send them to a remote server which has a fixed ip, saves the data and displays it on a ...
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NAT and UDP replies
Sanity check please.
If I send UDP packets from Machine A behind a NAT to Machine B's port N, where Machine B is outside the NAT (elsewhere on the Internet), can I reasonably expect that NAT to pass ...
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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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Why is my UDP so slow?
I'm using Iperf on two VMs and when using TCP I find the performance is as follows:
notroot@ubuntu:~$ iperf -s
------------------------------------------------------------
Server listening on ...
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3
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Netcat/socat behavior with piping and UDP?
I guess this is close to linux - Netcat stops listening for UDP traffic - Super User, but I thought I'd better ask anyways
As far as versions of netcat I'm using Ubuntu 11.04 and the default netcat ...
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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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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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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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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 machines),...
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What prevents unsolicited internet packets from using up my monthly data limit?
My home router can use port-forwarding to act as a server, so I assume all internet packets
sent with my public IP address as a destination are hitting it (and just not getting any
response from my ...
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Tunnel wireguard (or any UDP traffic) inside HTTPS
Wireguard is pretty hot these days, deservedly so. I'm also eager to replace OpenVPN by Wireguard.
However, unlike OpenVPN, Wireguard only supports UDP. I like to use TCP port 443 because this port ...
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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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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 play it in vlc?
udp:@:1234
Does not work for me. How to fix this?
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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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Wireshark - how can I observe little endian big endian difference in byte order using Wireshark?
I wrote a simple application which communicates using UDP sockets (in C). Application is simple: clients sends numbers to server, and server computes the sum of them.
Now, I know how can I capture ...
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Puzzling TCP performance over 3G / UMTS
I'm using 3G as my primary internet connection, and TCP over this thing is getting more puzzling every day. For example:
Downloading from kernel.org is crazy fast:
$wget http://www.kernel.org/pub/...
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Netcat stops listening for UDP traffic
I am using netcat on some Linux machines (see this other question), but seeing some unexpected behavior.
Unlike the guide in the accepted answer, I am not using UDP tunneling to do DNS queries. I ...
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Trouble with netcat over UDP
While troubleshooting the problem described here, I tried something really basic: I tried setting up a very basic netcat connection over UDP, and I noticed it's not working as I expect.
As with the ...
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Linux SOCKS5 tunneling not working with udp traffic
I am using the command ssh -N -D 0.0.0.0:1080 localhost which works perfectly fine for my web browser, but when I try and tunnel a UDP traffic application it doesn't work.
I thought that socks5 ...
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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 in ...
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HTTP vs TCP vs UDP with this example? [closed]
I can transfer the data from my application(assume java application) through either of three protocols i.e. http/TCP/UDP
HTTP example for java client is
TCP example for java client is
UDP ...
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How to deliberately introduce a delay for incoming UDP packets
I want each packet (that match iptables rule) to be delayed by some fixed time interval. How to to this?
Preudocode: iptables -A INPUT -p udp <more conditions> -j DELAY --delay 50000 # delay ...
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Why ICMP is different that TCP and UDP? [closed]
what is the difference between Internet Control Messaging Protocol over Transmission Control Protocol and User Datagram Protocol
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How does a proxy know where to forward the requests to?
When a proxy receives a connection how does the proxy know where to forward the request to?
For example in Java we can set a system property for proxy.
So we set the IP of the proxy and the request is ...
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Does TCP/UDP send file sequentially or randomnly?
Does TCP/UDP protocol always send or receive file packets sequentially? Would it possible to make a choice which data packets will be sent first using sockets API?
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DHCP: broadcast flag
I'm looking at some DHCP packets through wireshark. I notice that in the bootp section, there is a broadcast flag.
However, the dest IP is 255.255.255.255. Isn't it enough to indicate that it's ...
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Proxifier that supports UDP? [closed]
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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TCP vs UDP. Sending data on a closed port
I try to understand differences between TCP and UDP packet on the error-checking. I know that UDP packets are connectionless and doesn't care that the packet will arrive the destination safely. And ...
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Cannot play video stream from FFMPEG to VLC
I'm trying to stream my local webcam using FFMPEG. For test purposes, I'm doing this locally and try to open the stream using VLC (3.0.8, Windows 10). This is how I stream from FFMPEG:
ffmpeg -f ...
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SSH connection under UDP?
Is there a way to establish a SSH connection over UDP?
I'm running behind a "filter all inbound TCP traffic" firewall so I cannot utilize a SSH tunnel properly.
I have set up over at my brothers ...
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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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How to force a process transmit over UDP instead of TCP?
I 'm running an ffserver process on a Linux machine, in order to achieve video streaming via ffmpeg. However, there is a delay on video streaming. On ffserver configuration file I define Port 8090.
...
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How can I open a TCP/UDP connection on Linux?
I am looking for a simple command line tool to open TCP/UDP server/client on a desired port on a Linux machine. Are there any applications or commands that I can use to achieve this?
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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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What is the master process running on port 465?
I want to close non used ports in my server, after doing a port scan I found service urd running on port 465. Running lsof I see a "master" process running on that port (also 25, 587,etc..). Question ...
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Good process specific packet sniffer / viewer? [closed]
I am looking for a good, free or not free, packet sniffer.
The main feature I am looking for is an ability to watch a chosen process and view / read all of the data it is sending or receiving.
Also ...
Tanner Collin
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how do the world's peer to peer networks handle UDP hole punching?
With Bitcoin and Ethereum in the news so much I started to look into peer to peer networks more. My question is, do most of the people running full Bitcoin or Ether nodes have to open port 8333 to the ...
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Broadcast address in IPV4
I have a small network with the subnet mask 255.255.255.240 and the IP range is 192.168.2.1 - 192.168.2.12. From 192.168.2.1, I want to broadcast a packet. I don't want this packet to go anywhere ...
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How to use DNS over TCP?
Google DNS (8.8.8.8 and 8.8.4.4) are blocked (or polluted) by all ISPs available to me (and DNS by ISPs just return wrong answers for some sensitive sites!!), and it is said that if we change DNS from ...
user69835
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UDP with netcat on Mac OS
I try to connect to a Tello drone from my Mac by opening an UDP connection to 192.168.10.1 via port 8889 to send commands and receive ack's from the device.
When using "Packet Sender" it works, but ...
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Linux - Can I Duplicate, send, then and Deduplicate UDP packets?
I am transmitting UDP data across 2 Linux (Intel) based routers, and I am experiencing low levels of packet loss which are interfering with the application.
Is there a way (ideally, but not ...
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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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OpenVPN client behind corporate firewall
I cannot connect from the corporate network at work to my OpenVPN server. However, with client and server settings untouched, connecting from other networks works.
I can only assume that this is due ...
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OpenVPN connection breaks time to time: TLS Error: local/remote TLS keys are out of sync
We have our own VPN in my workplace. Everyone has its own key. However I am the only one who works on linux, the rest use either Macs or Windows machines. Unfortunately I have not found any good ...
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UDP broadcasting not working on some routers?
I have a game that runs on mobile devices and connects two of them together by using UDP Broadcast and simultaneously listening and broadcasting. On most home WiFi networks, this works well (corporate ...
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