The Ident service as specified by RFC 1413 is mostly used by various IRC networks and the occasional old FTP server to ask a remote server which user is making a connection. This method is quite untrustworthy, as the remote host can simply choose to lie.
So you have two choices:
- Tell the truth (see #oidentd below)
- Tell a little white lie (see nullidentdmod or nullidentd below)
If all went well, you should have the auth service running on port 113. A good way of checking this is by installing(if you do not have it already) and typing
$ nmap localhost
Install the AUR package.
Check if is working here.
As is, nullidentdmod will return a random userid.
Create a replacement unit file for
# systemctl edit --full nullidentdmod@.service
At line 6, write desired userid
[Unit] Description=NullidentdMod service [Service] User=nobody ExecStart=/usr/bin/nullidentdmod <userid> StandardInput=socket StandardOutput=socket [Install] WantedBy=multi-user.target
Obviously where <userid> you put your custom userid.
Check if is working here
This Ident server is capable of only returning the same name for any query. With a quick change to a single line of code, it can be customized to return any name you can think. One use for such a simple service would be for IRC client connections to ensure a degree of privacy (remote IRC server and users do not know your username) as well as allowing a small degree of 'vanity plating' for use in IRC channels.
The original code suffered link rot, but may now be found on github, at this address https://github.com/dxtr/nullidentd.
/etc/systemd/system/identd@.service, Add the following:
[Unit] Description=per connection null identd [Service] User=nobody ExecStart=/usr/local/sbin/nullidentd StandardInput=socket StandardOutput=socket
/etc/systemd/system/ident.socket, Add the following:
[Unit] Description=socket for ident [Socket] ListenStream=113 Accept=yes [Install] WantedBy=sockets.target
Inform systemd of the new files:
# systemctl daemon-reload
Test that the socket is listening sucessfully:
$ systemctl status ident.socket
this should yield output similar to the below
ident.socket - socket for ident Loaded: loaded (/etc/systemd/system/ident.socket; enabled) Active: active (listening) since Fri 2014-01-24 02:30:53 WST; 30 seconds ago Listen: [::]:113 (Stream) Accepted: 0; Connected: 0 Jan 24 02:30:53 HOSTNAME systemd: Listening on socket for ident.