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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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Sending a UDP message to a computer inside a network

Say I have the ip and mac address of a computer inside a network and I wish to send him a UDP message. By initializing the mac and ip addresses of the sent message to the given, when the network router recives the message he should pass it to the…
Dan
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How to simulate high wire speed ？

I want to test the max speed of my VPN(pptp) server, so I plan to download something from one server by VPN, At first, I think the server need to supply a high speed(30M) for client, who can tell me how to do this, thanks!
larry
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How to prioritize openvpn traffic?

I have an openvpn server, with one network interface. VPN traffic is extremely slow. I tried to do traffic control with this configuration (currently): qdisc del dev eth0 root qdisc add dev eth0 root handle 1: htb default 12 class add dev eth0…
aditsu
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Make bridge table with UDP packet

Assume that all bridge table was empty (or at least don't have source and destination of my connection ) and want to update their bridge table with my sending packet (when I send packet all bridge understand where "Sender Host" are and when…
Amirreza
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Why are some UDP packets getting blocked?

In our organization, we have two test machines running Windows XP. While attempting to test a roll-my-own UDP message server, I found that both could receive small messages (under 2k) just fine. However, when I test sending large packets to both…
Tom A
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Is there a method to send UDP output to one logical NIC such that it gets sent out two physical NICs on different subnets?

I have an application that needs to send UDP multicast data "from" either one or two physical NICs on a single Windows Server 2008 machine. In the two NIC configuration, every datagram needs to be sent through both physical NICs. Each NIC is on a…
Patrick Johnmeyer
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Problem in creating UDP sockets

Our production server is running PostgreSQL v8.2.3 on Red Hat Enterprise Linux Server release 5 (Tikanga). For some reason, statistics collector in PostgreSQL is not working. Even posted this question in PostgreSQL mailing list here: Statistics…
Gnanam
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Altq limits not being applied to UDP transfers

I have a OpenBSD server acting as a router/firewall with yhr packet filter ruleset shown below, a linux server, and a linux client. When transferring files (using netcat) by TCP, the limits are applied (for example the 100mbit limit in the…
user42511
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Iptables REDIRECT + openvpn problem

I want to redirect connection to port 22 to my openvpn binded port, on 60001. Openvpn is running on server on 60001 server:~$ sudo netstat -apn | grep openvpn udp 0 0 67.xx.xx.137:60001 0.0.0.0:* 4301/openvpn I redirect on server port 22…
Emilio
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Sharepoint Ports

I am installing Sharepoint 2007 and I want users to be able to sign into it from outside. I need to know what ports do I need to open and do I need UDP or TCP or both?
Jack Levin
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Can't see udp packets with nc command, works with tcpdump

I'm trying to capture UDP data using the nc (netcat) command but it doesn't output anything. What options/parameters do I need to pass to the nc command to get the output? tcpdump does show the UDP data. The reason I'm trying nc is that when I know…
Martijn de Munnik
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Iptables duplicate/Mirror incoming UDP traffic from HOST1 to an external HOST2

I need an advice about the following scenario: IoT devices are sending UDP packets to a 18.04 Ubuntu server environment (HOST1) on port 1234. HOST1 processes the UDP packets as per the internal configuration I need to: Duplicate/mirror those…
user3132858
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Iptables: limit mdns packet per second per ip

I have a network with a lot of MDNS (UDP 5353) traffic on it. To avoid overloading my server, I limit globally the MDNS packets accepted by iptables with this rules: iptables -A INPUT -i eth2 -p udp --dport 5353 -m limit --limit 100/second -j…
cyanat
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Ubuntu Network: Allow UDP connection to Port B if a UDP connection was established to Port A before

I want to setup an IPv4 firewall for UDP connections to port :7777 with the following rules: By default block all connections to UDP Port :7777. Allow only whitelisted IPs connections to UDP Port :7777. If an IP has made a UDP connection to port…
Jeremy John
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UDP Port Forwarding

I got 2 servers Named A and B, both are in different data centers and just have internet access. I need the incoming UDP connections to a particular port on server A to be forwarded to a specific port on server B. ssh tunneling is just for TCP. I…
xtg
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