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This article refers to a server ban in IRC. For other meanings, see K-line (disambiguation).

A k-line or kill line, also written k:line, etc. is an Internet Relay Chat term, applied to a specific user. When a user is k-lined, it bans the user from a certain server, either for a certain amount of time or permanently. Once the user is banned they are not allowed back onto that server. They have to join a different server to get onto IRC, this is recorded as a line in the server's IRC daemon configuration file prefixed with the letter "K", hence "K-line".

Contents 1 Reasons 1.1 User behavior 1.2 Client software 1.3 Geographic location 2 Other "lines" 2.1 G:Line/AKill 2.2 Z-line 2.3 Q-line 3 See also 4 External links

While the precise reason for the disconnection varies from case to case, usual reasons involve some aspect of the client or the user it is issued against.

The most common cause for a k-line is inappropriate behavior on the part of the user, such as nickname colliding, mode "hacking", multiple channel flooding, harassing other users via private messaging features, spamming etc., or in the case of older networks without timestamping, split riding, which cannot be corrected through use of channel operator privileges alone.

Some IRC Daemons can be configured to scan for viruses or other vulnerabilities in clients connecting to them, and will react in various ways according to the result. Outdated and insecure client software might be blocked to protect other network users from vulnerabilities, for instance. Some networks, e.g. freenode, will disconnect clients operating on/via open proxies, or running an insecure web server.

An IRC network operating multiple servers in different locales will attempt to reduce the distance between a client and a server. This is often achieved by disconnecting (and/or banning) clients from distant locales in favour of local ones.

There are a number of other network "lines" relating to the k-line.

A Gline or AKill is a global network ban applied to a user; the former term comes from Undernet and the latter from DALNet. The term "AKill" comes from an earlier implementation in which the IRC Services would automatically "kill" (disconnect) the user remotely upon login, rather than the individual servers simply denying the connection.

On some IRCds, such as UnrealIRCd, a Zline is similar to a g-line, but applied to a client's IP address range, and is considered to be used in extreme cases. Because a Zline does not have to check usernames (identd) or resolved hostnames, it can be applied to a user before they send any data at all upon connection. Therefore a Zline is more efficient and uses less resources than a Gline or Kline when banning large numbers of users. Because not all IRCds are the same, others, such as Charybdis, use a 'Dline' instead.

On some IRCds, such as UnrealIRCd, a Qline forbids a nickname, or any nickname matching a given pattern. This is most often used to forbid use of services nicknames (such as 'X', or NickServ) or forbid use of IRC Operator nicknames by non-operators. Some IRC daemons may disconnect users when initially applying the Qline, whilst others will force a nickname change, or do nothing until the user covered by the Qline reconnects. Other IRCds, like Charybdis, use an 'Xline' instead.

• O-line
• Jupe
• OperServ

• Undernet K-Line and G-Line FAQ with reasons for them, amongst other things
• EFnet FAQ with several -line terms explained
• Quakenet General FAQ G/K-Line
• GLine, KLine, QLine and ELine syntax