Re: Invalid prefix passed to CEF SNMP Walker

manoj.3.joshi.con · ‎12-27-2009

Hi All,

We are observing error logs stating ‘Invalid prefix passed to CEF SNMP Walker’ on . The attachment shows the error logs.

Joe Clarke · ‎12-27-2009

This looks like CSCsi02671. This is fixed in 12.4(12b).

manoj.3.joshi.con · ‎12-27-2009

Hi Joe,

Thanks for the post. The same thing i got via online output Interpreter.

This is due to the known software bug CSCsi02671.

Please find below for your reference.

ERROR MESSAGE NOTIFICATIONS

WARNING:%FIB-4-FIBBADSNMPPREFIX: Invalid prefix passed to CEF SNMP walker ([IP_address][IP_netmask])

Explanation: when SNMP is polling the routing table, Gateway may generate tracebacks following with the above error message.

Recommended Action: Please upgrade the ios image to fixed / latest version.

Below is from Cisco Site:-

===============================================

Related Bug Information

SNMPwalking ipRouteTable may result in %FIB-4-FIBBADSNMPPREFIX traceback

Symptom: Doing snmpwalk of ipRouteTable in RFC1213-MIB, it may result in some traceback as seen below: Mar 5 22:31:33.980: %FIB-4-FIBBADSNMPPREFIX: Invalid prefix passed to CEF SNMP walker (0.0.0.1/0). -Traceback= 0x611C46F8 0x614A9944 0x6170CBF4 0x6170D1D4 0x61F520D8 0x61F56008 0x61F46F40 0x61F6F8B0 0x621E1560 0x621E1544 Conditions: This has been observed on the C3800 routers running 12.4(12a). Other versions and platforms may also be affected. Workaround: Create an SNMP view to block the SNMP server to poll the ipRouteTable. Here is an example: conf t snmp-server view cutdown internet included snmp-server view cutdown ip.21 excluded snmp-server community view cutdown RO

Cannot discover the Router using CA Ehealth after enabling IOS based IPS

Symptom After turning on the IOS IPS feature on a 2821 Router , it cannot be redicovered in CA Ehealth using SNMP. Workaround Workaround is to un configure the IOS IPS feature and then discovery starts working again.

They have suggested a workaround. Tried doing below configuration but no luck.

conf t

snmp-server view cutdown internet included

snmp-server view cutdown ip.21 excluded

snmp-server community cutdown RO

Joe Clarke · ‎12-28-2009

The configuration is wrong. The workaround would be:

conf t

snmp-server view cutdown internet included

snmp-server view cutdown ip.21 excluded

snmp-server community COMMUNITY cutdown RO

Where COMMUNITY is the your current SNMP community string. You would then poll the device with that community string. The downside of this workaround is that you can no longer poll the routing table. This may hinder network discovery or other management tasks which rely on the rotuing table. The recommended solution is to upgrade to 12.4(12b).