IRC with Emacs ERC and ZNC

Posted on Dec 30, 2025

RC is a protocol that is older than the Web and has a long history behind it. The protocol is still used, but it is not really something that the majority of mainstream messaging application users would get excited about. The protocol is open and free to use, and because of this, there is not much commercial interest in investing in applications that would attract “mainstream” users.

To use the protocol properly, you not only need an IRC client application, but also a so-called IRC bouncer - a sort of proxy between your IRC client of choice and the IRC server. The bouncer is a server application that runs 24 hours per day and monitors activity on the IRC channels (chat groups) to which the user is subscribed. While the user is away, the bouncer records all activity and replays it to the IRC client when the client reconnects. The client alone may connect directly to the IRC server, but this does not guarantee that the user will see all messages posted to a channel while he or she is away.

This requirement alone is a threshold that prevents the majority of potential users from ever considering an IRC-protocol-based client as their chat application of choice. You need to know what you are doing, and going through the hassle of setting up a bouncer is a test you must pass in order to fully participate in IRC-based communities.

My setup

There are many IRC clients and a number of bouncers that can be used. My preferred setup is based on IRC client build in Emacs called ERC and the ZNC bouncer.

How ERC, ZNC, and IRC Interact

Here’s a simple diagram of how the components work together.

How it works:

ERC client connects to ZNC bouncer running on a server.
ZNC stays connected to the IRC server 24/7, recording messages while you are away.
ERC fetches messages from ZNC, so you never miss conversations.

IRC nick name registration

The first thing that needs to be arranged in order to participate in the IRC network is the registration of your chosen IRC nickname.

Go to an IRC server that hosts the channels you want to subscribe to (for example, libera.chat) and register your nickname using the following command:

/msg NickServ REGISTER IRC_password your@email.address.com

IRC_password = your chosen password
your@email.address.com = your email address

You can use a web client provided by the IRC server to register without an IRC client. If the nickname is available, it will be registered.

ZNC setup

Follow the installation instructions provided by the ZNC website but also keep in mind that the bouncer should run on a machine that is active 24 hours a day. Your laptop is not a good choice. You may consider Raspberry Pi or similar board to set it up as a server.

Once installed, use znc --makeconfig to generate an initial configuration. Follow prompts to set up your ZNC username, password, and server port.

Finally start the service and access the web administration interface.

Open https://localhost:ZNC_port in a browser.
Log in with your ZNC username and password.
Use Manage Users to configure the IRC networks and channels.

You can also set up a SASL authentication module to automatically authenticate with the IRC server using your registered IRC nick name and password.

ERC configuration

Once the ZNC setup is complete, it is time to configure your client. Below is the basic configuration for ERC, my IRC client of choice.

Uncomment irc in the :app section of in the ~/.config/doom/init.el configuration file to enable ERC .

(doom! :app
      irc
      )

Include the following configuration into the ~/.config/doom/config.el file.

(require 'erc)

(setq auth-sources '("~/Sync/shared/.authinfo.gpg" "~/.authinfo.gpg" "~/.authinfo" "~/.netrc"))

(defun my-erc ()
  "Connect to my ZNC bouncer."

  (interactive)
  (erc-tls
   :server "ZNC_server_address"
   :port ZNC_port
   :nick "IRC_nick_name"
   :password (auth-source-pick-first-password :host "ZNC_server_address")))

The configuration provides all the information needed for ERC to connect to the ZNC bouncer.

ZNC_server_address: IP address or domain name of the ZNC server
ZNC_port: The port you have chosen for ZNC access
ZNC_password: The ZNC user password
IRC_network: The name of the network set during ZNC configuration
IRC_nick_name: The IRC nick name you have registered

It ensures that ERC can locate the server running ZNC and authenticate with it using the password you have set for your ZNC user.

The ZNC authentication parameters must be provided in the ~/.authinfo file located in your home directory. The file format is as follows.

machine ZNC_server_address login IRC_nick_name password ZNC_user_name/IRC_network:ZNC_password port ZNC_port

Ensure your password consists of these three parameters:

ZNC_user_name/IRC_network:ZNC_password

Once you have finished editing your configuration, execute the doom sync command in a terminal. This will apply your changes and update Doom Emacs. After the command completes, restart Emacs to ensure that the new configuration is loaded.

To start ERC, run the command M-x my_erc inside Emacs. ERC will then attempt to connect to your ZNC bouncer using the credentials and server information you set up.

Once connected, ERC will create a separate buffer for each IRC channel you subscribed to when configuring your IRC network. You can switch between these buffers using standard Emacs buffer commands, such as C-x b.

After everything is working, you can start chatting immediately and ERC will automatically keep track of messages on your subscribed channels even while you are away thanks to ZNC.

Troubleshooting

If the connection fails, check that:

ZNC is running and accessible at the server address and port you specified.
Your .authinfo file contains the correct ZNC username and password.