Lab  7.4.3 IGRP Default Network 

Objectives:

  • Use a default network with IGRP to setup a gateway of last resort on all IGRP routers.

Scenario: 

You have an IGRP routing domain with only one outside link. You want all routers to send packets to that gateway, if there is not an explicit route listed in the routing table.

Lab Task:

  1. Cable the lab and all interfaces as shown in the diagram.

  2. Configure IGRP routing on all routers.

    Router-a(config)#router IGRP 109
    Router-a(config-router)#network 192.168.11.0
    Router-a(config-router)#network 192.168.9.0

    Router-b(config)#router IGRP 109
    Router-b(config-router)#network 192.168.10.0
    Router-b(config-router)#network 192.168.11.0
    Router-b(config-router)#network 192.168.12.0

    Router-c(config)#router IGRP 109
    Router-c(config-router)#network 192.168.10.0

  3. Verify that IGRP is configured correctly and all routes are listed in the routing table. On Router C the 10.0.0.0 network should be directly connected, but not listed in the routing table of the other routers.

  4. Is there a gateway of last resort set in the routing tables of all the routers? Try to ping and trace to 10.1.1.1 and 10.1.1.2 from Router A and Router B. Does it work? Record your answers below.




  5. Configure Router C to advertise a gateway of last resort.

    Router-c(config)#ip route 10.0.0.0 255.0.0.0 10.1.1.254 Router-c(config)#ip default-network 10.0.0.0 Router-c(config)#router igrp 109 Router-c(config-router)#redistribute static 

  6. Issue the command show ip route on all routers to see if the candidate default route is listed. Is there a gateway of last resort listed in the routing table of every router?