How to read the routing table?

ajarina · ‎05-12-2002

Which route for 192.168.0.150 should be used for this entry?

C 192.168.0.0 is directly connected, Ethernet0/0

S 192.168.0.128 [200/0] via 192.168.1.2

Please note that the static entry is subnetted. I just wanted to know if the specific subnet is prioritzed even it has a larger AD.

DALE FRANCIS · ‎05-13-2002

If you are using IP classless it will always use the longest match..

ajarina · ‎05-13-2002

I am using IP classless, what do you mean by longest match? the subnetted one?

If I will use another static entry with a lower administrative distance. Will it be erased from the routing table as soon as gets invalid, thus utilizing the secondary route?

DALE FRANCIS · ‎05-13-2002

As far as i remember (cisco should verify) when you insert a static it WILL check the next hop address or if pointed to and interface ( if will become "connected").

If you insert a static with lower AD then it will replace the one currently in the routing table, we often use this for redundancy.

Eg:

ip route 0.0.0.0 0.0.0.0 192.247.3.1 100

ip route 0.0.0.0 0.0.0.0 192.247.3.2 200

the 1st one should be inserted into routing table, if that next hop keels over and dies well presto..:))

Also have a look at your CEF table, that will give you a good indication of how traffic is being switched, we have seen CEF overide a routing table before. Kinda ODD but we have seen it happen..