Host mask

from Wikipedia, the free encyclopedia

A host mask is used in IRC networks to uniquely identify endpoints such as users or services, or to logically combine a large number of host names using wildcards . It is made up of the three components Nickname , Ident and Host (according to the scheme Nickname! Ident @ Host ).

Host masks play a crucial role in server-to-server and server-to-user communication, as the recipient and sender are identified not by their nickname, but by the host mask.

Many networks partially hide the host in order to make the IP addresses of the respective users inaccessible, which otherwise could easily be found out via DNS lookup.

Examples of identifying host masks:

  • Erik!erik@pD9049B86.dip.t-dialin.net
  • Susi!sissi@12345-aol.com
  • Peter!test@XXXXX.t-dialin.net (disguised by the server)

Examples of host masks with wildcards:

  • erik! * @ * (matches all endpoints that have erik as a nickname)
  • *!*@*.t-dialin.net (matches all endpoints whose host ends on .t-dialin.net )

Hostnames with wildcards are mainly used to keep certain user groups out of chat rooms. For example, the host mask *!*@*.de , if it is included in the ban list, would deny most German users access.