Identd Setup

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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:

  1. Tell the truth (see #oidentd below)
  2. Tell a little white lie (see nullidentmod or nullidentd below)


See oidentd.

If all went well, you should have the auth service running on port 113. A good way of checking this is by installing nmap (if you do not have it already) and typing

$ nmap localhost


1. Install the nullidentdmod-gitAUR package.

2. Enable nullidentdmod.socket on systemd.

3. Start nullidentdmod.socket on systemd.

4. Check if is working here.

As is nullidentdmod will return a random userid.


1. Copy the unit for customization

# cp /usr/lib/systemd/system/nullidentdmod@.service /etc/systemd/system/

2. Edit /etc/systemd/system/nullidentdmod@.service At line 6, write desired userid

Description=NullidentdMod service        
ExecStart=/usr/bin/nullidentdmod <userid>

Obviously where <userid> you put your custom userid.

4. 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

1. clone the source to a directory of your choice using git.

git clone

2. Edit line 86 of nullidentd.c to your liking. use any text editor of your choice


nano nullidentd.c

3. Compile the binary.


4. Install Binary You can move it to any location of your choice of course, but the FileSystem Hierarchy states the nullidentd binary should live in /usr/local/sbin

# mv nullidentd /usr/local/sbin

systemd activation

Below are two files you need to create under /etc/systemd/system/

1. identd@.service

Description=per connection null identd


2. ident.socket

Description=socket for ident



3. inform SystemD of the new files

# systemctl daemon-reload

4. 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[1]: Listening on socket for ident.