Definition Statements

Definition statements are general configuration statements that relate to all of GateD or at least to more than one protocol. The three definition statements are autonomoussystem, routerid and martians. if used, autonomoussystem, routerid and martians must appear before any other type of configuration statement in gated.conf file.

Autonomous System configuration

  autonomoussystem autonomous_system [ loops number ] ;

Sets the autonomous system number of this router to be autonomous system. This option is required if BGP or EGP are in use. The AS number is assigned by the Network Information Center (NIC).

Loops is only for protocols supporting AS paths, such as BGP. It controls the number of times this autonomous system may appear in an AS path and defaults to 1 (one).

Router ID configuration

  routerid host ;

Sets the router identifier for use by the BGP and OSPF protocols. The default is the address of the first interface encountered by GateD. The address of a non-point-to-point interface is preferred over the local address of a point-to-point interface and an address on a loopback interface that is not the loopback address (127.0.0.1) is most preferred.

Martian configuration

martians { host host [ allow ] ; network [ allow ] ; network mask mask [ allow ] ; network masklen number [ allow ] ; default [ allow ] ; } ;

Defines a list of martian addresses about which all routing information is ignored. Sometimes a misconfigured system sends out obviously invalid destination addresses. These invalid addresses, called martians, are rejected by the routing software. This command allows additions to the list of martian addresses. See section 4.25.1 on for more information on specifying ranges. Also, the allow parameter may be specified to explicitly allow a subset of a range that was disallowed.

Sample Definition Statements

autonomoussystem 249 ; martians { 0.0.0.26 };

The statements in the sample perform the following functions:

• The autonomoussystem statement tells GateD to use AS number 249 for in EGP and BGP.
• The martians statement prevents routes to 0.0.0.26 from ever being accepted.