SNMP + Null Routes

gskhanna · ‎12-16-2007

Platform: Cisco 6500, and Cisco 3550

1)I want to read via SNMP, all routes that have been nulled.

2)I want to be able to put in new null routes.

3) I want to be able to remove null routes.

ie: read and write: ip route 1.1.1.1 255.255.255.255 Null0 314324

I've looked and looked but could not find an OID that even came close to this, or any information online how how to add a null route via snmp or add a static route via snmp.

I need this information so I can automate some null routes that our system need to implement from time to time, and remove them as well.

Thank you for your help.

-Gurpreet

Joe Clarke · ‎12-16-2007

Reading routes is doable using the ipRouteTable objects. For example, this CLI:

ip route 10.10.10.0 255.255.255.0 Null0

Would look like the following in the ipRouteTable:

RFC1213-MIB::ipRouteDest.10.10.10.0 = IpAddress: 10.10.10.0

RFC1213-MIB::ipRouteIfIndex.10.10.10.0 = INTEGER: 27

RFC1213-MIB::ipRouteMetric1.10.10.10.0 = INTEGER: 0

RFC1213-MIB::ipRouteMetric2.10.10.10.0 = INTEGER: -1

RFC1213-MIB::ipRouteMetric3.10.10.10.0 = INTEGER: -1

RFC1213-MIB::ipRouteMetric4.10.10.10.0 = INTEGER: -1

RFC1213-MIB::ipRouteNextHop.10.10.10.0 = IpAddress: 0.0.0.0

RFC1213-MIB::ipRouteType.10.10.10.0 = INTEGER: direct(3)

RFC1213-MIB::ipRouteProto.10.10.10.0 = INTEGER: local(2)

RFC1213-MIB::ipRouteAge.10.10.10.0 = INTEGER: 0

RFC1213-MIB::ipRouteMask.10.10.10.0 = IpAddress: 255.255.255.0

RFC1213-MIB::ipRouteMetric5.10.10.10.0 = INTEGER: -1

RFC1213-MIB::ipRouteInfo.10.10.10.0 = OID: SNMPv2-SMI::zeroDotZero

In this example, ifIndex 27 is Null0.

While these objects are read-write, you will not be able to create new routing table entries via SNMP (only modify existing entries).

Creating routes is supported in the new IP-FORWARD-MIB (using the ipCidrRouteTable), but this table is not supported on the 3550, and I do not know what code your 6500 is running.