Ban masks explained: nick!user@host format

When moderating an IRC channel on AustNet, effective bans rely on understanding how server-side bans work. Simply banning a troublesome user's nickname is rarely enough because nicknames can be changed instantly. Instead, channel operators use ban masks built around the standard IRC hostmask format.

1. The Anatomy of a Hostmask (nick!user@host)

Every user connected to AustNet has a unique identifier assigned by the server, structured in three distinct parts separated by an exclamation point (!) and an at symbol (@):

1. nick: The user's current nickname.
2. user: The username (ident) reported by the user's client or ident server.
3. host: The user's hostname or masked gateway address (such as a +x user cloak).

An example of a full hostmask looks like:

TroubleMaker!ident@austnet/user/randomstring

2. Why Banning Only a Nickname Is Not Enough

If a disruptive user is causing problems in a channel and an operator types /mode #channel +b BadNick, the protection is easily bypassed:

1. Instant Nickname Changes: The user can simply type /nick NewNick and continue their disruptive behavior immediately.
2. Temporary Scope: A nickname-only ban targets a transient label rather than the underlying connection, making it ineffective against persistent trolls or automated scripts.

3. Writing Effective Ban Masks with Wildcards

To prevent a user from simply changing their nickname or reconnecting with minor variations, operators use wildcards (* for multiple characters, ? for a single character) to create broad, robust ban masks.

Depending on how specific you want the ban to be, you can target different layers of the hostmask:

1. Targeting Nickname and Host:
2. BadNick!*@* (Blocks a specific nickname across any user/host combination, though they can still change names).
3. Targeting Username and Host (Recommended):
4. *!ident@austnet/user/randomstring (Locks out the specific user identity and hostcloak regardless of what nickname they change to).
5. Targeting an Entire ISP or Subnet:
6. *!*@*.broadband-provider.net or using IP wildcards if uncloaked, to block an entire range of disruptive connections.

Once a ban mask is set using /mode #channel +b <mask>, any user matching that pattern will be blocked from joining or kicked from the channel if they are already inside.