Strange outside ARP entry in ASA5505
Posted on 2011-09-20
I have the strangest problem. I have a static IP to my ISP and hence configured a static outside route to my ISP, which works without issues. However, after a while the internet is unavailable (the time is random). My outside interface on the ASA appears to be working but I simply cannot access the internet.
After some research I've discovered that when the problem occurs, the ASA has recently received a very strange ARP entry on the outside which points to "some location", I don't know what....
The really strange thing is that my old firewall (before the ASA) does not receive this ARP entry so I'm pretty sure it has something to do with the ASA.
Both the old firewall and the ASA has "automatic ARP" on the outside interface but I don't understand where this ARP entry comes from, but every time it gets added to the ARP cache the internet stops working.
Thanks in advance.