is a small tool to redirect UDP traffic. It
can be used as a poor man's filtering tool, e.g. for small multihomed embedded
systems without a built-in firewall.
forwards packets to a specified destination
remembering the sender's address, any packets received from the destination
are in turn forwarded to the sender.
is launched from
it does not
immediately exit when the first reply has been forwarded. Instead it lingers
for three (3) seconds in case more requests are received, e.g. in the case of
an SNMP walk. This helps conserve precious system resources, useful in
particular on embedded systems.
For a TCP port redirector, try
, which now
has the same maintainer as
- Print a summary of the options and exit
- Run in inetd mode, read data from stdin. Implies
-n, always runs in foreground
- Identity, tag syslog messages with the ID name, default:
- Set log level: none, err, info, notice (default),
- Run in foreground, do not detach from controlling
- Use syslog, even if running in foreground, default w/o
- Set timeout to SEC seconds for connections, default 3
- Show program version
- Source, or outer/public, IP and UDP port to bind to, the
SRC can be left out to default to 0.0.0.0. Must not be set when running in
inet mode, -i
- Destination, or inner/private, IP and UDP port to redirect
This simple UDP proxy example forwards inbound DNS requests on any interface to
an external DNS server on 192.168.0.1.
uredir :53 192.168.0.1:53
To run uredir
in inetd mode, e.g. to redirect SNMP
requests, and timeout after 5 sec, try the following. Runs in foreground, as
required for inetd services, and uses syslog for logging:
snmp dgram udp wait root uredir -it 5 127.0.0.1:16161
Syntax may vary between different inetd implementations and UNIX distributions.
Use the project's GitHub page to file bug reports, feature requests or patches
-- preferably as pull requests
used to be based on
by Ivan Tikhonov, but is today based
on youdp by Tobias Waldekranz. Current maintainer is Joachim Nilsson.