"Show ip route" L - Local

Unanswered Question
Sep 6th, 2010

I have just issued the 'sh ip route' command and the router output is showing some of the routes as 'L'

I have the expected Connected 'C' and OSPF 'O'  routes but I have not seen the 'L' indicator before. I have done a search but can't find anything that explains why the /32 interface addresses have been marked as Local

ROUTER#sh ip route
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

.

<OUTPUT OMITTED>

.

C        XX.YYY.1.64/30 is directly connected, GigabitEthernet0/0
L        XX.YYY.1.66/32 is directly connected, GigabitEthernet0/0
C        XX.YYY.1.68/30 is directly connected, GigabitEthernet0/1
L        XX.YYY.1.70/32 is directly connected, GigabitEthernet0/1

These connections are configured as point to point OSPF connections for connecting the router to core switches, and the routers themselves are used as BGP Route Reflectors. Can anyone shed any light on the meaning of 'Local' and why it is needed as well as  'Connected'. I can do a 'sh ip route connected' but it doesn't allow 'sh ip route local'

These are c7301 routers running IOS 12.2(33)SRD

Regards

Mel

I have this problem too.
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Peter Paluch Mon, 09/06/2010 - 04:58

Hello,

Recent versions of the IOS software started displaying these local prefixes in the IPv4 routing table. As far as I know, this was always the case with IPv6 routing table and IPv6 addresses, and now it has been also adopted for the IPv4 routing table.

These entries do not basically tell you anything new as they merely state an obvious fact: your own IP address is reachable on a particular interface. Having this route in a routing table merely makes sure that the packet destined for your IP address will not be rerouted but rather processed locally. I believe that these entries were in the routing table even before they started being displayed, they just were hidden.

This is my idea about this.

Best regards,

Peter

Mel Popple Tue, 09/07/2010 - 01:02

Peter,

Thanks for the response. I will check out some of the IPv6 documentation. Pity there wasn't a response from the Cisco TAC guys with a difinitive answer but at least I have a starting point.

Regards

Mel

Probably no one will read this 4 years after, but just for thread comletion's sake (and since gougle returns this page in its results) I cut-paste the following passage form the CCNA 100-101 cert guide(Chapter 16 after Example 16-1).

"Note that the router also automatically produces a different kind of route, called a local route. The local routes defines a route for the one specific IP address configured on the router interface. Each local route has a /32 prefix length, defining a host route, which defines a route just for that one IP address. For example, the last local route, for 172.16.5.1/32, defines a route that matches only the IP address of 172.16.5.1. Routers use these local routes that list their own local IP addresses to more efficiently forward packets sent to the router itself."

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