NAME

       oidentd - flexible, RFC 1413 compliant ident daemon with NAT support

SYNOPSIS

       oidentd [OPTIONS]

DESCRIPTION

       oidentd implements the Identification Protocol as described in RFC 1413. By default, oidentd replies with
       the username of the owner of connections. This behavior can be altered in oidentd.conf(5) and by using
       the options specified in this document.

OPTIONS

       -a, --address=ADDRESS
           Bind to the specified address. This option causes oidentd to listen for incoming connections only on
           the specified address or addresses instead of on all interfaces. This option may be specified more
           than once to configure multiple addresses.

       -c, --charset=CHARSET
           Inform clients that ident replies use the specified character set as defined in RFC 1340 or its
           successors. The default is not to send a character set to clients.

       -C, --config=FILE
           Use the specified system-wide configuration file. If this option is not given, oidentd defaults to
           /usr/local/etc/oidentd.conf. The format of the system-wide configuration file is described in
           oidentd.conf(5).

       -d, --debug
           Show debug messages, including detailed lookup information that may be useful for diagnosing issues
           with failed lookups. This option is only available if oidentd was compiled with debugging support.

       -e, --error
           Hide error messages, returning UNKNOWN-ERROR for all errors. This includes the NO-USER, HIDDEN-USER
           and INVALID-PORT errors. This option may be used to conceal the fact that oidentd is hiding ident
           responses for a user.

       -f, --forward=[PORT]
           Forward requests for hosts masquerading through the server oidentd is running on to the host that
           established the corresponding connection. The target host must be running oidentd with the --proxy
           option, or some ident server returning static responses regardless of the query. If no port is
           specified, the default ident port (113) is used. If forwarding fails, oidentd falls back to the
           response specified in oidentd_masq.conf(5). This option implies --masquerade. The --masquerade-first
           option can be used to forward queries only if no response was specified in oidentd_masq.conf(5).

       -g, --group=GROUP|GID
           Run as the specified group or GID. If this option is not given, oidentd falls back to running as
           "oidentd", "nobody", "nogroup" or GID 65534, in this order. On systems that require oidentd to run as
           the superuser, a warning is shown and the group is not changed automatically.

       -h, --help
           Print a summary of options and exit.

       -i, --foreground
           Do not fork to background. This option may be useful for debugging, or for running oidentd from a
           service manager like systemd(1) with Type=simple.

       -I, --stdio
           Read a single ident query from standard input, write the response to standard output, then exit. This
           option may be useful for debugging, or when running oidentd from a listener daemon such as xinetd(8).

       -l, --limit=MAX
           Limit the maximum number of concurrent connections to the specified value. Further connections beyond
           this limit will be closed immediately without spawning a new process. If this option is not
           specified, no limit is enforced.

       -m, --masquerade
           Enable support for NAT connections, allowing Ident lookups intended for hosts masquerading through
           the server running oidentd. Ident responses for NAT connections can be configured in the
           oidentd_masq.conf(5) configuration file.

       -M, --masquerade-first
           If an entry matching the target host exists in the oidentd_masq.conf(5) configuration file, return
           the configured Ident response instead of forwarding the query. With this option, queries are
           forwarded only if no static response has been configured. If this option is not specified, the
           default behavior of --forward is to forward queries before checking the oidentd_masq.conf(5) file.
           This option implies --forward and --masquerade.

       -o, --other=[OS]
           Set an alternative operating system string to send alongside ident responses. Note that some clients
           may interpret queries as having failed when an unknown operating system is returned. If this option
           is not specified, the value UNIX is used. If this option is specified without an argument, OTHER is
           returned.

       -p, --port=PORT
           Listen on the specified port instead of port 113.

       -P, --proxy=ORIGIN
           Allow the specified host to forward queries to this instance using the --forward option. If --reply
           is not specified, this option must be enabled for oidentd to correctly handle forwarded connections.

       -q, --quiet
           Suppress normal logging, showing only critical messages.

       -r, --reply=REPLY
           When a lookup fails, send the specified ident response as if it had succeeded.

       -R, --reply-all=REPLY
           Send the specified reply in response to all well-formed queries. When this option is used, the
           configuration files are not read and connection lookups are never performed. Privileged
           initialization is not performed on systems that would otherwise require it, so unprivileged users can
           run oidentd with this option as long as they have permission to bind the requested port.

       -S, --nosyslog
           Log messages to the standard error stream, even if it is not a terminal. If standard error is a
           terminal, messages are written to it by default.

       -t, --timeout=SECONDS
           Close connections if no ident query is received within the specified number of seconds. By default,
           connections are closed after 30 seconds.

       -u, --user=USER|UID
           Run as the specified user or UID. If this option is not given, oidentd falls back to running as
           "oidentd", "nobody" or UID 65534, in this order. On systems that require oidentd to run as the
           superuser, a warning is shown and the user is not changed automatically.

       -U, --udb
           Look up connection owners using libudb. Lookup results that do not match any local user are returned
           verbatim. If a UDB lookup fails, the operating system is queried directly. This option also applies
           to NAT connections if the --masquerade option is specified.

       -v, --version
           Print version and build information and exit.

FILES

       /usr/local/etc/oidentd.conf
           System-wide configuration file; see oidentd.conf(5).

       ~/.config/oidentd.conf, ~/.oidentd.conf
           User configuration files; see oidentd.conf(5).

       /usr/local/etc/oidentd_masq.conf
           Masquerading configuration file; see oidentd_masq.conf(5).

AUTHOR

       Janik Rabe <oidentd@janikrabe.com>
           https://oidentd.janikrabe.com

       Originally written by Ryan McCabe.

BUGS

       Please report any bugs to Janik Rabe <oidentd@janikrabe.com>.

SEE ALSO

       oidentd.conf(5) oidentd_masq.conf(5)