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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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Multicast works only in promiscuous mode

I'm trying to receive MPEG-TS over UDP multicast transport in Arch Linux. So when I run ffprobe -i udp://@224.1.1.240:6000 it hangs forever with no result. Then I run tcpdump and it shows no multicast traffic from the address. But if there is…
TrueBers
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Monitoring /proc/net/udp

I am interested in tracking changes in /proc/net/udp, particularly in the "drops" column. I want to know the the approximate time when a drop counter goes up. Also, if the socket gets destroyed, I want a record of what the drop count was. I am…
user583933
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Is Linux limiting my application's UDP transfers, and how can I see it?

I am currently developping two applications to work over a custom video streaming "protocol". Basically: The server captures video frames from a webcam, slices them into parts, and sends these parts to the clients over UDP. The clients receive all…
John WH Smith
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Linux: Reduce UDP Packets Error

I'm facing UDP packet receive errors (under Linux 'netstat -su' command). I have 10 x UDP processes running on Machine-A (RHEL 5.2) and each of them send 290-byte packet at 50 times per second to the same address and same UDP port. On the recipient…
tanlccc
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UDP Proxy with cloned packets

Having UDP messages sent from dynamic public IP periodically to public IP X:20000. Need a proxy that listens in IP X:20000, then forwards duplicate/clone packets to X:20001 and a different machine located in IP Y:20000. Now, when application…
jacktrades
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Are DNS server responses categorized as "ESTABLISHED" by iptables? If so, why?

CentOS 5.x I'm trying to confirm which specific rule in my iptables config is allowing return UDP traffic from my DNS server. I THINK, it's this one: -A RH-Firewall-1-INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT If I take off RELATED and…
Mike B
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tcpreplay throughput on eth0 well below (iperf confirmed) max

I'm trying to replay captured UDP multicast packets at a rate of a couple of hundreds of Mbps, but it maxes out at about 86 Mbps. (For some strange reason, at other times during the day it consistently maxes out at one tenth of that rate, about 8.8…
Evgeniy Berezovsky
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How to see log of apps taking specific port over period of time on Windows?

How can I see for specific time period, which app had bound some specific port in Windows? I am auto-starting my app with windows and I am bounding port 1200 as UDP packet receiver, but sometimes my app reports that the port is taken. Can I see…
Saša Šijak
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Does Azure support UDP Broadcast?

I am aware that Azure supports UDP, but does it support UDP broadcast? I am wanting to use the Jenkins Swarm plugin, which requires UDP broadcast for new slaves to join the master.
DonBecker
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How can I determine if my VPN is passing through UDP traffic?

I have an client application that is unable to connect with it's server counterpart over a VPN connection. Server is Windows SBS 2011, client is Windows 7 64bit Enterprise. Using Windows VPN client. I can ping the server and browse it's drives,…
Steve K
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What is the equivalent of 127.255.255.255 for OS/X machines so I can test broadcast udp packets without a network?

I am trying to test my program that makes use of broadcast UDP (not multicast!). In Linux, I can use the 127.255.255.255:64651 address and everything works beautifully, in other words, I send a packet to 127.255.255.255:64651 and multiple clients…
JohnPristine
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Why is qemu issuing a DHCP discover after it receives a DHCP offer

I'm having some trouble seting up network on qemu. I'm trying the easy option (user). The qemu command I run is this: ./qemu-xilinx/arm-softmmu/qemu-system-arm \ -M xilinx-zynq-a9 -m 1024 -serial null -serial mon:stdio \ -dtb…
fakedrake
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In need of a SNMP repeater

I have a monitoring system that has primary/failover nodes for just about every aspect. I have configured anything that is able for multiple SNMP trap destinations, but I do have a number of devices that only support a single trap destination. What…
Michael Moser
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Minimal size of TCP communication

I am sending small amounts of data (up to 100 bytes) every 10 minutes from devices to TCP server. In my case overhead seems to be huge (we pay for each byte). I found that I have at least 7-10 packets (three-way handshake (3), request with ack(2),…
ruruskyi
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Serious Packet Loss on UDP using Amazon EC2

I am using ec2 to host a udp TURN server for SIP purpose. Anyway I get a lot of packet loss during voice call, so I did a udp performance test using iperf util. Result: [ ID] Interval Transfer Bandwidth Jitter Lost/Total…
Jason
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