Ironport customercare told us that to fix the DoS everyone will have to upgrade to the latest version AsyncOS 4.5.
An aside - I think the Symantec purchase of Brightmail has taken the "shine" off Brightmail. From my personal experience the quality of the support for Brightmail has dimished since it joined the Symantec Supermarket - although spammers have probably caught up with Brightmail.
We have configured the outside and inside Interface with official ipv6 adresses, set a default route on outside Interface to our router, we also have definied a rule , which also gets hits, to permit tcp from inside Interface to any6.
In Syslog I also se...