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# User Datagram Protocol (UDP)
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The [UDP](/UDP) layer provides datagram based connectionless transport layer (layer 4) functionality in the [InternetProtocolFamily](/InternetProtocolFamily).
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UDP is only a thin layer, and provides not much more than the described UDP port multiplexing.
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Just like [IP](/IP), UDP doesn't provide any mechanism to detect [PacketLoss](/PacketLoss), [DuplicatePackets](/DuplicatePackets), and the like.
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There are a lot of protocols on top of UDP, including: [BOOTP](/BOOTP), [DNS](/DNS), [NTP](/NTP), [SNMP](/SNMP), ...
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### UDP-Lite
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Are you looking for Lightweight UDP? Then visit [UDP-Lite](/UDP-Lite).
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## History
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XXX - add a brief description of UDP history
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## Protocol dependencies
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- [IP](/IP): Typically, UDP uses [IP](/IP) as its underlying protocol. The assigned protocol number for UDP on IP is 17.
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## Example traffic
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XXX - Add example traffic here (as plain text or Wireshark screenshot).
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## Wireshark
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The UDP dissector is fully functional.
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There are two statistical menu items for UDP available: *Statistics/Endpoints* which contains a tab showing all UDP endpoints (combination of IP address and UDP port) and *Statistics/Conversations*, which contains a tab showing all UDP conversations (combination of two endpoints).
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## Preference Settings
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(XXX add links to preference settings affecting how UDP is dissected).
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## Example capture file
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XXX - Add a simple example capture file. Keep it short, it's also a good idea to gzip it to make it even smaller, as Wireshark can open gzipped files automatically.
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## Display Filter
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A complete list of UDP display filter fields can be found in the [display filter reference](http://www.wireshark.org/docs/dfref/u/udp.html)
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Show only the UDP based traffic:
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```
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udp
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```
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## Capture Filter
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Capture only the UDP based traffic:
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```
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udp
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```
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## External links
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- [RFC768](http://www.ietf.org/rfc/rfc768.txt) User Datagram Protocol
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## Discussion
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---
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Imported from https://wiki.wireshark.org/User_Datagram_Protocol on 2020-08-11 23:27:09 UTC |