Upgraded a 5510 to 8.0 yesterday. At some point last night all access to inside services from the outside stopped. After several hours of complete frustration today trying to get it back up I found that a command had been added.
sysopt noproxyarp outside
Why would this have been added from the upgrade? Basically the outside router could not arp any of the addresses inside the firewall which prevented the outside services from functioning. I removed it and everything worked again. The reason it worked originally is because the arp was cached in the outside router for 4 hours. Wouldn't you think that would disabled by default?