"Clear arp" restores connection on ASA5520

[cosmin.cucu]

Hello,

I have a ASA5520 setup in my test environment, 0/0 is the internet interface ( with static IP ) , the other 3 interfaces having other servers / acces points / switches connected. Yesterday morning , all of a sudden ( after not even logging to the ASA for a month i think ) , the connection dropped. I had to leave, but in the evening, when i started debugging i found out that after a "clear ARP", the connection is restored, for about 5-30 seconds, after which it drops again. Behind and on the firewall, everything works, servers get ip's from the DHCP server, all can communicate normally. They just can't reach out, and from outside the public interface cannot be reached ( also a anyconnect VPN there ) . Late evening, after one more clear arp , it just worked, untill this morning, when it started acting up again.

Anyone has an idea what it might be?

Thanks,

Cosmin

[jumora · Accepted solution]

Log into the ASA and run a debug ARP when you see the failure, run a clear arp and wait for it to fail, you might see a ARP collision indication who could be the source or the problem. Also check de logs, set them to debugging level for asdm and go to monitoring > logging> real time log viewer. You should see ARP collisions

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