This software is in the public domain.
Written by Peter Postma <peter@pointless.nl>
.Dd January 31, 2004 .Dt IDENTD 8 .Os .Sh NAME .Nm identd .Nd TCP/IP Ident protocol server .Sh SYNOPSIS .Nm .Op Fl 46beIilNnr .Op Fl a Ar address .Op Fl c Ar charset .Op Fl F Ar format .Op Fl f Ar fallback .Op Fl g Ar uid .Op Fl L Ar username .Op Fl o Ar osname .Op Fl p Ar portno .Op Fl t Ar seconds .Op Fl u Ar uid .Sh DESCRIPTION .Nm is a TCP/IP server which implements the user identification protocol as specified in RFC 1413.
p .Nm operates by looking up specific TCP/IP connections and returning information which may or may not be associated with the process owning the connection.
p The following options are available: l -tag -width XXxXusernameXX t Fl 4 Bind to IPv4 addresses only. (flag .Fl b only) t Fl 6 Bind to IPv6 addresses only. (flag .Fl b only) t Fl a Ar address Bind to the specified .Ar address . This may be an IPv4 or IPv6 address or even a hostname. If a hostname is specified then .Nm will resolve it to an address (or addresses) and will bind this address. (flag .Fl b only) t Fl b Run in the background (as daemon). t Fl c Ar charset Specfify an optional character set designator to be included in replies. .Ar charset should be a valid charset set as described in the .Tn MIME RFC in upper case characters. t Fl e Return .Dq UNKNOWN-ERROR instead of the usual .Dq NO-USER or .Dq INVALID-PORT error replies. t Fl F Ar format Specify the format to display info. The allowed format specifiers are: d -literal %u print user name %U print user number %g print (primary) group name %G print (primary) group number %l print list of all groups by name %L print list of all groups by number .Ed
p The lists of groups (%l, %L) are comma-separated, and start with the primary group which is not repeated. Any other characters (preceded by %, and those not preceded by it) are printed literally. The .Dq default format is %u, and you should not use anything else without using the flag .Fl o Ar OTHER . t Fl f Ar fallback Specify a .Ar fallback username. If the lookup fails then this username will be returned. This can be useful for when running this service on a NAT host. t Fl g Ar gid Specify the group id number or name which the server should switch to after binding itself to the TCP/IP port. t Fl I Same as .Fl i but without the restriction that the username in
a .ident must not match an existing user. t Fl i If the
a .ident file exists in the home directory of the identified user, return the username found in that file instead of the real username. If the username found in
a .ident is that of an existing user, then the real username will be returned. t Fl L Ar username Specify a .Dq lie .Ar username . Return this name for all ident requests. t Fl l Use .Xr syslogd 8 for logging. t Fl N Enable
a .noident files. If this file exists in the home directory of the identified user then return .Dq HIDDEN-USER instead of the normal USERID response. t Fl n Return numeric user IDs instead of usernames. t Fl o Ar osname Return .Ar osname instead of the default .Dq UNIX . t Fl p Ar portno Specify an alternative port number under which the server should run. The default is port 113. (flag .Fl b only) t Fl r Return a random name of alphanumeric characters. If the .Fl n flag is also enabled then a random number will be returned. t Fl t Ar seconds Specify a timeout for the service. The default timeout is 30 seconds. t Fl u Ar uid Specify the user id number or name to which the server should switch after binding itself to the TCP/IP port. .El .Sh FILES
a /etc/inetd.conf .Sh EXAMPLES .Nm operates from .Xr inetd 8 or as standalone daemon. Put the following lines into .Xr inetd.conf 5 to enable .Nm as an IPv4 and IPv6 service via inetd:
p ident stream tcp nowait nobody /usr/libexec/identd identd -l
p ident stream tcp6 nowait nobody /usr/libexec/identd identd -l
p If you want to run .Nm as standalone daemon then please use the .Fl b flag (background). .Sh SEE ALSO .Xr inetd.conf 5 , .Xr inetd 8