"no route" count is increasing

[akgupt89]

I am below error on DC Cisco Nexus.

"The following routers experienced a large number of 'no routes' in the prior 24-hour period. The default value is 5000 'no routes' but may be different depending on device group settings. The 'no route' counter is incremented whenever the router receives a packet that cannot be forwarded for any reason."

Kindly help how to resolve this error.

[Giuseppe Larosa]

Hello @akgupt89,

you should provide more information in order to get better help.

What model of Nexus is involved ?  Are they configured as a vPC pair ?

post a show version to see also the NX-OS version.

What kind of configuration and services are deployed on them ?

For standard IP routing it would be enough to check if you have a default route installed in the routing table to avoid this.

But your Nexus could be configured for something more complex like:

OTV  or   BGP EVPN for DC interconnect

In these cases the answer might be less trivial

Hope to help

Giuseppe

[michael.thomas]

I am actually looking into this issue myself and came across this thread. The "issue description" is actually generated from NetMRI. I am trying to determine what counter is being increased as well (and why) I have a 93180YC-EX running 9.2.1. I do Run BGP down to a couple NSX clusters. This does not trigger log messages (with default logging level). The description of the error is:

The 'no route' counter is incremented whenever the router receives a packet that cannot be forwarded for any reason. One reason is that no system replied to an ARP request by the router. Ping sweeps of sparsely populated subnets will generate large numbers of 'no routes'. Such ping sweeps may be due to network discovery processes and may be due to worms or viruses on the network. Another reason is that the packet contained a destination address that didn't correspond to any route in the routing table. An example is an application that is using an invalid IP address, either hard coded into the application or obtained from an out of date DNS entry. A network analyzer is typically required to troubleshoot such problems.

I realize I am resurrecting a possibly dead thread, but this may help some else later on.