C9500 High Performance - ARP learned but not working, need clear ARP

[osw200051]

Hi Expert,

I encountered a case under Cisco C9500 high Performance model. my client connect and get the IP address, gateway point to C9500. But not reachable. Show ARP in C9500, the ARP entry is correct.

After the action "clear ip arp x.x.x.x" in C9500, the IP is connected. Did anyone encounter the same issue? Is it the BUG on C9500?

Thanks

[MHM Cisco World]

can you share more info.
are you config any L2 security like DHCP & ARP snooping ?
are you config any port-security ?
the client not reachable ? what you meaning here?

[Jitendra Kumar]

Not have much information on that to advise you correctly yes what you can do on the client.

check with windows firewall off.

netsh winsock reset use below command windows client.

Here is the very good discussion you should have to learn 

https://learningnetwork.cisco.com/s/question/0D53i00000Kt2ImCAJ/about-ping-and-arp-table

[balaji.bandi · Accepted solution]

I encountered a case under Cisco C9500 high Performance model. my client connect and get the IP address, gateway point to C9500. But not reachable. Show ARP in C9500, the ARP entry is correct.

is this from device to Switch or switch to device ?

after clear arp entry are you able to ping each other from switch to device and device to switch ?

is this SVL ? what is IOS-XE code running ?

[osw200051]

Hi balaji.bandi,

Cisco C9500 is the core switch. It connects to C2960X, and C2960X connects to client PC. 

subnet gateway locates at C9500. It is SVL ip subnet for client. 

Before clear the arp, the arp record is correct (true IP and mac address), but cannot ping the PC from C9500. After clear the arp and learned again, it can ping. And after the action, client PC can connect to internet again.

Thanks

[lagerplane · Accepted solution]

A bug that matches your workaround (clearing the ARP entry) is https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvm45417 , but need to confirm those details that @balaji.bandi just mentioned.