Introduction

ZNC is a powerful IRC (Internet Relay Chat) bouncer (commonly called a "BNC") that keeps you connected to IRC servers even when your IRC client is offline. Instead of connecting directly to an IRC network, your IRC client connects to ZNC, and ZNC maintains the connection to the IRC server on your behalf.

This allows you to reconnect at any time without losing messages or your nickname, making ZNC an essential tool for users who spend a lot of time on IRC.

What Is ZNC?

ZNC is an open-source IRC bouncer that acts as an intermediary between your IRC client and an IRC server.

The connection works like this:

IRC Client
     │
     ▼
   ZNC Server
     │
     ▼
 IRC Network

Instead of disconnecting from IRC when you close your client or lose your internet connection, ZNC remains online 24/7 and continues to receive messages, maintain your nickname, and stay connected to channels.

When you reconnect, ZNC can play back messages you missed while you were away.

Why Use ZNC?

ZNC offers several advantages over connecting directly to IRC.

Stay Connected

Your IRC nickname remains online even if:

• You close your IRC client
• Your computer shuts down
• Your internet connection drops
• You switch devices

Playback Missed Messages

One of ZNC's most useful features is its playback capability.

If someone sends messages while you're offline, ZNC stores them so you can read them after reconnecting.

Connect from Multiple Devices

You can use multiple IRC clients simultaneously.

For example:

• Desktop computer
• Laptop
• Mobile phone
• Tablet

All devices stay synchronized through the same ZNC instance.

Secure Connections

ZNC supports:

• SSL/TLS encryption
• Client certificates
• Password authentication
• IPv4 and IPv6

Modular Design

ZNC supports modules that add functionality such as:

• Message playback
• Push notifications
• Logging
• Auto replies
• Web administration
• Buffer management

Common Use Cases

People use ZNC to:

• Stay online 24/7
• Never miss IRC conversations
• Connect from multiple devices
• Maintain a persistent nickname
• Log IRC activity
• Manage multiple IRC networks

System Requirements

ZNC runs on:

• Linux
• FreeBSD
• OpenBSD
• NetBSD
• macOS

It can also be compiled on Windows, although Linux is the most common deployment platform.

Installing ZNC

Ubuntu/Debian

sudo apt update
sudo apt install znc

CentOS/Rocky Linux

sudo dnf install znc

Build from Source

Download the latest source code.

wget https://znc.in/releases/znc-latest.tar.gz

Extract it.

tar -xzf znc-latest.tar.gz
cd znc-*

Compile:

./configure
make
sudo make install

Initial Configuration

Run:

znc --makeconf

The setup wizard asks questions such as:

• Username
• Password
• Listening port
• SSL support
• IRC network
• IRC nickname
• IRC server
• Channel list

Example:

Username: john
Password: ********
IRC Server: irc.libera.chat
Port: 6697
SSL: Yes
Nickname: JohnIRC
Channels: #linux #chat

After the wizard finishes, ZNC creates its configuration files automatically.

Starting ZNC

Launch ZNC:

znc

Run it in the background:

znc -d

Connecting Your IRC Client

Instead of connecting directly to an IRC server, connect your IRC client to your ZNC server.

Example:

Server: your-server.com
Port: 6697
Username: username/network
Password: yourpassword
SSL: Enabled

Your IRC client now connects to ZNC, and ZNC connects to the IRC network.

Web Administration

ZNC includes a built-in web interface for managing users, networks, and modules.

Open your browser and visit:

https://your-server:port/

From the web interface you can:

• Add IRC networks
• Change passwords
• Enable modules
• Configure channels
• View logs
• Manage users

Useful ZNC Modules

Some of the most popular modules include:

Loading Modules

From your IRC client:

/msg *status LoadMod log

List loaded modules:

/msg *status ListMods

Unload a module:

/msg *status UnloadMod log

Managing Networks

Add a network:

/msg *status AddNetwork Libera

Connect:

/msg *status Connect

Disconnect:

/msg *status Disconnect

List networks:

/msg *status ListNetworks

Playback Buffers

One of ZNC's best features is message buffering.

When disconnected:

1. ZNC stays online.
2. Messages are stored.
3. You reconnect.
4. Missed messages are replayed automatically.

This means you don't lose conversations while you're away.

Running ZNC as a Service

On systems using systemd:

systemctl --user enable znc
systemctl --user start znc

Check its status:

systemctl --user status znc

Security Best Practices

To secure your ZNC installation:

• Use SSL/TLS for client connections.
• Choose a strong administrator password.
• Keep ZNC updated.
• Restrict access with a firewall.
• Enable two-factor authentication if available through your authentication setup.
• Regularly back up your configuration.

Advantages of ZNC

• Maintains a persistent IRC connection.
• Never miss important messages.
• Connect from multiple devices.
• Supports multiple IRC networks.
• Includes a web administration interface.
• Lightweight and efficient.
• Extensible with modules.
• Open source and actively maintained.

Limitations

• Requires a server or VPS that is always online.
• Initial configuration can be more complex than a direct IRC connection.
• Message playback consumes some disk space over time if logging or large buffers are enabled.

Who Should Use ZNC?

ZNC is ideal for:

• IRC enthusiasts.
• Open-source contributors.
• System administrators.
• Developers.
• Community moderators.
• Anyone who wants a persistent IRC presence.

Conclusion

ZNC is one of the most popular IRC bouncers available, allowing you to stay connected to IRC networks around the clock. By acting as a persistent intermediary between your IRC client and the IRC server, it keeps your nickname online, stores missed messages, and lets you connect from multiple devices seamlessly.

Whether you are an occasional IRC user or manage several channels across multiple networks, ZNC provides a reliable and flexible way to improve your IRC experience. Its support for secure connections, multiple networks, message playback, and extensible modules makes it a valuable addition to any IRC setup.

Most Used ZNC Commands

ZNC is managed primarily through the *status pseudo-user. You send commands to *status from your IRC client using /msg *status <command>. These commands let you manage networks, modules, users, and your ZNC instance without leaving IRC.

Note: Some commands require administrator privileges. Available commands may vary depending on your ZNC version and installed modules.

Basic Commands

Network Management

List Networks

/msg *status ListNetworks

Shows all configured IRC networks.

Add a Network

/msg *status AddNetwork Libera

Creates a new IRC network named Libera.

Delete a Network

/msg *status DelNetwork Libera

Removes the specified network.

Connect to a Network

/msg *status Connect

Or specify a network:

/msg *status Connect Libera

Disconnect from a Network

/msg *status Disconnect

Server Management

Add an IRC Server

/msg *status AddServer irc.libera.chat +6697

The + before the port indicates an SSL/TLS connection.

Remove a Server

/msg *status DelServer irc.libera.chat +6697

List Servers

/msg *status ListServers

Displays all configured IRC servers for the current network.

Channel Management

Join a Channel

/msg *status Join #linux

Leave a Channel

/msg *status Part #linux

List Channels

/msg *status ListChans

Shows all configured channels.

Module Commands

List Available Modules

/msg *status ListAvailMods