1UREDIR(1)                 BSD General Commands Manual                UREDIR(1)
2

NAME

4     uredir — UDP port redirector
5

SYNOPSIS

7     uredir [-hinsv] [-I ID] [-l LVL] [-t SEC] [[SRC]:PORT] [DST]:PORT
8

DESCRIPTION

10     uredir is a small tool to redirect UDP traffic.  It can be used as a poor
11     man's filtering tool, e.g. for small multihomed embedded systems without
12     a built-in firewall.
13
14     uredir forwards packets to a specified destination remembering the
15     sender's address, any packets received from the destination are in turn
16     forwarded to the sender.
17
18     When uredir is launched from inetd(8) it does not immediately exit when
19     the first reply has been forwarded.  Instead it lingers for three (3)
20     seconds in case more requests are received, e.g. in the case of an SNMP
21     walk.  This helps conserve precious system resources, useful in particu‐
22     lar on embedded systems.
23
24     For a TCP port redirector, try redir(1), which now has the same main‐
25     tainer as uredir(1).
26

OPTIONS

28     -h      Print a summary of the options and exit
29
30     -i      Run in inetd mode, read data from stdin.  Implies -n, always runs
31             in foreground
32
33     -I ID   Identity, tag syslog messages with the ID name, default: process
34             name
35
36     -l LVL  Set log level: none, err, info, notice (default), debug
37
38     -n      Run in foreground, do not detach from controlling terminal
39
40     -s      Use syslog, even if running in foreground, default w/o -n
41
42     -t SEC  Set timeout to SEC seconds for connections, default 3
43
44     -v      Show program version
45
46     [SRC]:PORT
47             Source, or outer/public, IP and UDP port to bind to, the SRC can
48             be left out to default to 0.0.0.0.  Must not be set when running
49             in inet mode, -i
50
51     [DST]:PORT
52             Destination, or inner/private, IP and UDP port to redirect to
53

EXAMPLE

55     This simple UDP proxy example forwards inbound DNS requests on any inter‐
56     face to an external DNS server on 192.168.0.1.
57
58             uredir :53 192.168.0.1:53
59
60     To run uredir in inetd mode, e.g. to redirect SNMP requests, and timeout
61     after 5 sec, try the following.  Runs in foreground, as required for in‐
62     etd services, and uses syslog for logging:
63
64             snmp dgram udp wait root uredir -it 5 127.0.0.1:16161
65
66     Syntax may vary between different inetd implementations and UNIX distri‐
67     butions.
68

SEE ALSO

70     redir(1) inetd(8)
71

BUGS

73     Use the project's GitHub page to file bug reports, feature requests or
74     patches -- preferably as pull requests
75     ⟨https://github.com/troglobit/uredir⟩
76

AUTHORS

78     uredir used to be based on udp_redirect by Ivan Tikhonov, but is today
79     based on youdp by Tobias Waldekranz.  Current maintainer is Joachim Nils‐
80     son.
81
82BSD                             17 April, 2016                             BSD
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