Command
No Auto-Summary
Use
Prevents RIP from advertising networks as a classful boundary.
Syntax
Router(config-router)#no auto-summary
Example
Here’s the route table from R2 with auto-summary enabled.
| R2#show ip route Codes: C – connected, S – static, R – RIP, M – mobile, B – BGP D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2 E1 – OSPF external type 1, E2 – OSPF external type 2 i – IS-IS, su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2 ia – IS-IS inter area, * – candidate default, U – per-user static route o – ODR, P – periodic downloaded static route Gateway of last resort is not set R 1.0.0.0/8 [120/1] via 10.1.1.1, 00:00:03, FastEthernet0/0
|
Heres what happens to the routing tables when no auto-summary is enabled.
| R1#conf t Enter configuration commands, one per line. End with CNTL/Z. R1(config)#router rip R1(config-router)#no auto-summary |
| R2#show ip route Codes: C – connected, S – static, R – RIP, M – mobile, B – BGP D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2 E1 – OSPF external type 1, E2 – OSPF external type 2 i – IS-IS, su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2 ia – IS-IS inter area, * – candidate default, U – per-user static route o – ODR, P – periodic downloaded static route Gateway of last resort is not set 1.0.0.0/32 is subnetted, 3 subnets |
