Later this evening i wanted to access a IPv6 enabled website (streams.xenim.de) and the UTM showed me the error "Address family not supported by protocol" (s. attached screen shot).
Log entry:
2012:03:08-23:09:44 whity httpproxy[4378]: id="0002" severity="info" sys="SecureWeb" sub="http" name="web request blocked" action="block" method="GET" srcip="2001:5c0:x:x:x:x:x:e58e" dstip="79.140.41.30" user="" statuscode="502" cached="0" profile="REF_DefaultHTTPProfile (Default Proxy)" filteraction="REF_DefaultHTTPCFFAction (Default content filter action)" size="2675" request="0x10a94cd0" url="static.streams.xenim.de/.../Business Forums"
Then i recognized that the tunnel broker is not connected anymore (because of the reboot earlier). It was still enabled, but not connected. After restarting it, the site worked again.
So i tried to find the real reason why this occurs. And i think it's because of the DNS cache. IPv6 access to the Internet doesn't work anymore, but the DNS cache of the UTM still has the IPv6 address in his cache and returns it to the client, which then tries to access to the IPv6 address which fails.
Disabling the tunnel broker if the IPv6 enabled site is in the DNS cache has the same effect btw.
Don't know what would be the best way to prevent this behavior.
