# Sample Exterior Gateway Configurations

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### RIP/EGP Configuration

This configuration enables both an interior (RIP) and an exterior (EGP) protocol and sets certain protocol specific parameters.

        #  generate a default route if an EGP  neighbor is acquired
        #
        options gendefault ;
        #
        # define the autonomous system number for EGP
        #
        autonomoussystem 303 ;
        #
        # enable RIP
        #
        rip yes ;
        #
        # enable EGP with hello interval 1 1/2 minute, poll
        #  interval 10 minutes, neighbors 26.6.0.103 and 26.20.0.72
        #
        egp yes {
            packetsize 24488 ;
            group minhello 1:30 minpoll 10:00 {
               neighbor 26.6.0.103 ;
               neighbor 26.20.0.72 ;
            } ;
        } ;
        #
        # announce 136. 66 to AS 183
        #
        export proto egp as 183 {
            proto direct {
                136.66 metric 0 ;
            } ;
        } ;
        #
        # announce default via RIP with a metric of 3
        #
        export proto rip interface 136.66.12.1 {
               proto default {
                    announce 0.0.0.0 metric 3 ;
               } ;
        } ;

The AS number 303 is defined early as it is a definition statement and must occur before the first protocol statement. EGP is enabled by the `yes` in the EGP statement, which defines additional EGP parameters e.g. the `packetsize` parameter defining the initial size of update packets accepted, the `group` clause which sets parameters for all of the EGP neighbors in the group, and `minhello` and `minpoll` used to set the protocol timers. The first `export` statement directs GateD to use EGP to advertise the network (136.66.0.0) to the Internet. This is the address of the network, not of a gateway. The second `export` statement is used to announce the default route to subnet 136.66.12.0 with a metric of 3.

### BGP/OSPF Configuration

                                                      P2P
                                                       |
                      Router ID = 19.1.1.18            |  OSPF
              Backbone (area 0.0.0.0)		   |
                      AS Number = 1019                 |
                                                       |  BGP
              IGP
                                                       |
                     Network:            119.2.128.18  |
              09.1.1.19
                     119.2.128                   ______|______
                 EN  ---------------------------|             |
                     OSPF area 0.0.0.2          |             |
              BGP External to AS 2021
                                                |   Router A  |-
              -------------------- FR
                     Network:                   |             |
              21.1.1.21
                     119.4.128                  |             |
                 EN  ---------------------------|_____________|
                     OSPF area 0.0.0.2   119.4.128.18
         In   this   sample   configuration,  GateD  implements   the
         transformation  of  distance metrics  between  the  internal
         (OSPF)  and  external  (BGP) protocols.   Autonomous  system
         1019, of which GateD is a member, contains network 19.0.0.0.
         The   GateD   machine  has  several  interfaces  into   this
         autonomous system.  GateD is using BGP to peer with AS 2021,
         neighbor 21.5.1.21.

                        / etc / gated.conf
                        # # # # # # # # # # # # # # # # # # #
                        interfaces {options all passive; };
                        autonomoussystem 1019;
                        routerid 19.1.1.18;
                        rip no;
                        hello no;
                        egp no;
                        bgp yes {
                         preference 50 ;
                         group type
                             External peeras 2021
                         {

                             peer 21.5.1.21
                                  ;
                         } ;
                           group type
                             IGP peeras 1019
                           {

                            peer 19.1.1.19
                               ;
                         } ;
                        } ;
                        ospf yes {
                         area 0.0.0.2 {
                           authtype none;
                          networks {
                            119.0.0.0 mask 255.0.0.0 ;
                           } ;
                         interface 119.2.128.18
                           cost 1 {
                            retransmitinterval 5;
                            transitdelay 1;
                            priority 1;
                            hello interval 10;
                            routerdeadinterval 40;
                           } ;
                         interface 119.4.128.18
                           cost 1 {
                            retransmitinterval 5;
                            transitdelay 1;
                            priority 1;
                            hellointerval 60;
                            routerdeadinterval 180;
                           } ;
                         } ;
                         backbone {
                           authype none;
                         interface 19.1.1.19
                           cost 1 {
                            retransmitinterval 5;
                            transitdelay 1;
                            priority 1;
                            hellointerval 60;
                            routerdeadinterval 180;
                           } ;
                         } ;
                        } ;
                        export proto ospfase type 1 {
                         proto bgp as 2021 {
                           ALL
                            metric 1;      };
                         proto direct {
                           ALL
                            metric 1;  };
                        } ;
                        export proto bgp as 2021 {
                         proto direct {
                           ALL
                            metric 1;      } ;
                         proto ospfase {
                           ALL
                            metric 1;      } ;
                        } ;

In this configuration two autonomous systems (one internal, one external) are directly connected through a router that is attached to a backbone speaking OSPF. The AS number 1019 is defined early as it is a definition statement that occurs again in the first protocol statement which enables BGP. The first `export` statement directs GateD to advertise routes from the internal group AS 1019 running OSPF as the IGP gathering routing information to the external group AS 2021 using BGP. Routes to two local ethernets in AS 1019, identified as 119.2.128.18 and 119.4.128.18 (119.0.0.0 mask 255.0.0.0), are advertised along with the OSPF backbone (19.1.1.19.) The parameters for AS path, path origin and transitive optional attributes including transmission intervals are defined. The second `export` statement announces the default route to AS 2021 with a metric of 1.

Last updated 1995/04/19 18:42:16.

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