The Tcl core has supported TCP sockets via socket since version 7 or so, but UDP must be supplied by an extension.
- UDP in the Tcl core
- Trivial FTP
Tcl UDP Extensions
The following extensions provide UDP support:
- The normal package for standard UDP client/server programs. It is quite simple to use.
- An extensive TCP/IP package which also supports UDP
- An SNMP package with its own UDP implementation
- Access to raw IP Datagram and thus to UDP
- Communications EndPoints for Tcl
- A few Tcl routines for manipulating network packets
- UDP extension
- a small and clean critcl-based extension written in 2011 by CMcC
- Datagrams and Udp For Tcl
UDP enabled packages
PT: The dns package in tcllib is capable of using udp if available. So are the time and ntp packages.