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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.

Because UDP doesn't rely on handshaking to guarantee that packets arrive and in order it can be seen as an unreliable protocol, but for real time systems where acting on the data immediately is the most important consideration not having to wait for delayed packets is a distinct advantage.

UDP is just one communications protocol on the web. Others include:

  • Transmission Control Protocol (TCP)
  • Internet Control Message Protocol (ICMP)
  • Hypertext Transfer Protocol (HTTP)
  • Post Office Protocol (POP3)
  • File Transfer Protocol (FTP)
  • Internet Message Access Protocol (IMAP)

UDP on Wikipedia

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Routing inbound and outbound udp traffic to the same port in kubernetes

This is a follow-up to a prior question I asked, but with a different ask/approach. In case it matters, I'm on GKE, but I'm hoping there's a cloud-agnostic answer. I'm trying to run the container factoriotools/factorio, but the application has some…
xenrelay
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Kubernetes managing many distinct UDP servers on GKE

I'm trying to set up a system that can automatically spin up and down video game servers as docker images. In this case, factoriotools/factorio-docker. Each game is a different, distinct single-pod deployment of that container, and therefore (in the…
xenrelay
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when router sends ICMP protocol error message how does it set it's own TTL?

when using (traceroute -q 1 serverAddress), we know that it starts with TTL(Time to Live) = 1. when it goes through router, the router decrements TTL by 1. If TTL becomes 0 at that router, it sends back ICMP error TTL exceeded message. Now, tell me…
David Roonie
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Debian udp port fowrding to another server does not work?

I have PC A (192.168.255.126, eth1) and it will receive some UDP packets, port: 51000. Now I wish the PC A will automatically forward the UDP packets to PC B (192.168.255.127) I have found many solutions but all of them don't work. Solution…
user647673
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NGINX UDP Proxy Pass to HTTP

I built a NGINX reverse proxy where I listen for UDP traffic on port 53 and pass it on to an HTTP endpoint with modified headers. Once the headers are modified, I send the packet to the target. http.conf http { include /etc/nginx/mime.types;…
Brundlfly
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How 2 dynamic (external) IP devices can talk to each other via 1 static (external) IP

I have 3 devices: Device 1 (Dynamic IP): A raspberry Pi sending UDP packets to Device 2 via 4G modem via Internet Device 2 (Static IP): My Ubuntu/Windows PC with static IP, successfully receives packets from Device 2 by using NAT port Device 3…
Văn Hóa Vũ Nguyễn
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Forwarding UDP traffic from one host to another

I have two hosts, each with 2 network interfaces: host1: eth0:172.16.125.5 eth1:172.165.8.55 host2: eth0:172.16.125.6 eth1:172.165.8.56 I want to forward all UDP traffic to host1:eth1 port 1234 to host2:eth1 port 1234, i.e. 172.165.8.55:1234 ->…
BillA
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Increased CPU interrupts, degraded performance on upgrade to Symfony flex

We're upgrading our Symfony 3.4 app (LAMP w/ opcache/php-fpm) to flex (as per https://symfony.com/doc/current/setup/flex.html). In load testing, we're seeing increased CPU usage, particularly system CPU. Changes we've noticed in…
Matt
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Video streaming via UDP on gigabit ethernet = packet lost

We are observing a strange behavior on a video streaming application over UDP on the same LAN. The sender send an H264 video via UDP through ethernet configured as 1000BaseT-FD, the receiver receive the video through the ethernet cable in…
gib
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ncat script to test source IP addresses with UDP load balancer

I have two Ubuntu Virtual Machines behind an Azure Load Balancer. I'm observing some inconsistencies with the source IP addresses set in outgoing UDP packets from the VM's. I'm trying to come up with a simple ncat command or script that I can run on…
sipsorcery
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upstream timed out (110: Connection timed out) while proxying connection - Nginx/Raspberry Pi/Ubuntu 20.04

I cannot find any help with UDP, so I have come here to ask. I have a DNS cluster set up on Raspberry Pis running Ubuntu 20.04 and Nginx. The proxy is used for UDP on port 53. I am needing to put this into production, however, I'm weary because I…
DevOpsSauce
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How does the A record change over time by running a DNS query?

I am running a DNS query on www.wikipedia.org using Google's public resolver @8.8.8.8 using the mac terminal. I have to get the A records for the host and run the query a couple of times to notice any change to the A records. dig @8.8.8.8…
Danny Boy
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iptables udp port forwarded but ICMP UDP Port unreachable

I wish to host a game server (Zandronum Doom) on port 10666 UDP, but no one can connect to it. I have troubleshot the problem and I think it's a problem with my routing. My physical network architecture is like this: [WAN] - [Router] - [Switch] -…
FalcoGer
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iptables - perfect forwarding of port range to single port - p2p NAT traversal - how to keep the source UDP port untouched on the server?

To all the iptables gurus out there: I'm doing a little research on the viability of doing UDP hole punching to achieve NAT traversal in my network - I'm trying to figure out which UDP ports EXACTLY can be used for P2P connections between two peers…
Fanick
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What GCP product to use to run Docker container exposing a range of UDP ports to public internet

I am confused about which GCP product to use such that I can run a Docker container e.g. like "docker run -p 5001-5110:5001-5110/udp hunter_ctrl_standalone:latest -s foo". The container will use ca. 2 GB of RAM, 1 CPU. No load balancing needed. It…
vanosten
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