Identd - ArchWiki

# Identd

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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 nullidentdmod or nullidentd below)

## oidentd

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

## nullIdentdMod

1. Install the nullidentdmodAUR 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.

### Customization

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Reason: Creating a drop-in file would be better. (Discuss in Talk:Identd#)

1. Create a replacement unit file for `nullidentdmod@.service`:

    # 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.

4. Check if is working here

## nullIdent

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.

### systemd activation

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

1. identd@.service

    [Unit]
    Description=per connection null identd

    [Service]
    User=nobody
    ExecStart=/usr/local/sbin/nullidentd
    StandardInput=socket
    StandardOutput=socket

2. ident.socket

    [Unit]
    Description=socket for ident

    [Socket]
    ListenStream=113
    Accept=yes

    [Install]
    WantedBy=sockets.target

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.

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