Protecting Your Channel

How to Protect Your Channel from Spam and Attacks

Spam and flood attacks are still a reality on IRC. While network-level protections exist, channel owners and operators often need to react quickly when a specific channel becomes a target.

In most cases, these attacks are performed by automated bots connecting through traditional IRC clients. Webchat users, who connect via web browsers, are generally not involved and do not have the technical ability to generate large-scale floods.

For this reason, the most effective channel-level protections focus on restricting unauthenticated users and IRC client connections (the main class), while keeping the channel accessible to legitimate users.

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Mute Unauthenticated Users (Recommended First Step)

Almost all automated spam originates from unauthenticated nicknames. A good first response is to allow users to join the channel while preventing unauthenticated users from sending messages.

This can be achieved by applying a mute ban, for example:

With this approach, registered users connecting from the "main" class can continue sending messages normally, while unauthenticated users and/or bots are effectively silenced, keeping the channel accessible without locking it down. Webchat users are not affected, allowing the channel to remain accessible without being locked down.

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Restricting IRC Client Connections

If the attack continues, additional restrictions can be applied specifically to users connecting via IRC clients. Depending on the situation, operators may choose to either block or mute these connections.

To prevent unauthenticated IRC client users from joining the channel:

To allow them to join but prevent them from speaking:

These measures are usually temporary and can be relaxed once the attack subsides.

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Blocking Known Sources

In some cases, attacks originate from a specific server, hosting provider, or even a particular hostmask. When such a pattern is identified, channel-level bans can be used to stop further joins from that source.

For example, if attackers are connecting through the nexus.hybridirc.com server, the following ban can be applied:

Geographic restrictions can also be used in a similar way when necessary:

Or to block only unauthenticated users from a specific country:

Inverted bans can be used to allow access from only one country:

This would silence unauthenticated users connecting from the domain f3netze.de.

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Requiring Secure Connections

As an additional layer of protection, channels may require users to connect using SSL/TLS. Many poorly written bots do not support encrypted connections, making this an effective mitigation during active attacks.

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Terminology and Ban Mask Reference

The following ban mask components are used throughout this page. Understanding these terms will help channel operators apply precise and effective restrictions during spam or attack situations.

Example: