NAME
identd
- TCP/IP Ident protocol server
SYNOPSIS
identd
[-46beIilNnr]
[-a address]
[-c charset]
[-F format]
[-f username]
[-g uid]
[-L username]
[-m filter]
[-o osname]
[-P address]
[-p portno]
[-t seconds]
[-u uid]
DESCRIPTION
identd
is a TCP/IP server which implements the user identification protocol
as specified in RFC 1413.
identd
operates by looking up specific TCP/IP connections and returning
information which may or may not be associated with the process owning
the connection.
The following options are available:
- -4
-
Bind to IPv4 addresses only
(valid with flag
-b).
- -6
-
Bind to IPv6 addresses only
(valid with flag
-b).
- -a address
-
Bind to the specified
address.
This may be an IPv4 or IPv6 address or even a hostname.
If a hostname is specified then
identd
will resolve it to an address (or addresses) and will bind this address
(valid with flag
-b).
- -b
-
Run in the background (as daemon).
- -c charset
-
Specify an optional character set designator to be included in replies.
charset
should be a valid charset set as described in the
MIME RFC
in upper case characters.
- -e
-
Return
``UNKNOWN-ERROR''
instead of the usual
``NO-USER''
or
``INVALID-PORT''
error replies.
- -F format
-
Specify the format to display info.
The allowed format specifiers are:
%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
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.
- -f username
-
Specify a fall back
username.
If the lookup fails then this username will be returned.
This can be useful for when running this service on a NAT host and
not using the forward/proxy functionality.
- -g gid
-
Specify the group id number or name which the server should switch to after
binding itself to the TCP/IP port.
- -I
-
Same as
-i
but without the restriction that the username in
.ident
must not match an existing user.
- -i
-
If the
.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
.ident
is that of an existing user, then the real username will be returned.
- -L username
-
Specify a
``lie''
username.
identd
will return this name for all valid ident requests.
- -l
-
Use
syslogd(8)
for logging purposes.
- -m filter
-
Enables forwarding of ident queries.
The
filter
argument specifies which packet filter should be used to lookup the
connections, currently
`pf'
and
`ipfilter'
are supported packet filters.
Note that
identd
changes the ident queries to use the local port on the NAT host instead of
the local port on the forwarding host.
This is needed because otherwise we can't do a lookup on the proxy host.
On the proxy host,
``proxy mode''
should be enabled with the
-P
flag or
``lying mode''
with the
-L
flag.
- -N
-
Enable
.noident
files.
If this file exists in the home directory of the identified user then return
``HIDDEN-USER''
instead of the normal USERID response.
- -n
-
Return numeric user IDs instead of usernames.
- -o osname
-
Return
osname
instead of the default
``UNIX''.
- -P address
-
Specify a proxy server which will be used to receive proxied ident
queries from.
See also the
-m
flag how this operates.
- -p portno
-
Specify an alternative port number under which the server should run.
The default is port 113
(valid with flag
-b).
- -r
-
Return a random name of alphanumeric characters.
If the
-n
flag is also enabled then a random number will be returned.
- -t seconds
-
Specify a timeout for the service.
The default timeout is 30 seconds.
- -u uid
-
Specify the user id number or name to which the server should switch after
binding itself to the TCP/IP port.
FILES
/etc/inetd.conf
EXAMPLES
identd
operates from
inetd(8)
or as standalone daemon.
Put the following lines into
inetd.conf(5)
to enable
identd
as an IPv4 and IPv6 service via inetd:
ident stream tcp nowait nobody /usr/libexec/identd identd -l
ident stream tcp6 nowait nobody /usr/libexec/identd identd -l
To run
identd
as standalone daemon, use the
-b
flag.
SEE ALSO
inetd.conf(5),
inetd(8)
AUTHORS
This implementation of
identd
is written by
Peter Postma
<peter@NetBSD.org>.
CAVEATS
Since
identd
should typically not be run as a privileged user or group,
.ident
files for use when running with the
-I
or
-i
flags will need to be world accessible.
The same applies for
.noident
files when running with the
-N
flag.
When forwarding is enabled with the
-m
flag then
identd
will need access to either
/etc/pf
(pf) or
/etc/ipnat
(ipfilter).
Since it's not a good idea to run
identd
under root, you'll need to adjust group owner/permissions to the device(s)
and run
identd
under that group.