ProxyAV 810 running 18.104.22.168 frequently pings its default gateway.
ProxyAV 810 appliances running AVOS 22.214.171.124 periodically ping the default gateway to work around a rare network interface issue.
This issue only affects the ProxyAV 810 appliances and the pinging behavior only occurs on AVOS 126.96.36.199. As soon as the network interface issue is resolved, the ping workaround will be removed. (as of the 31/5/2012 the Ping will still occur in all Proxy AV releases)