It appears likely that within the next two quarters we will be moving off of our IPv4 class C's and onto a single IPv6 /40 for our sites.

We have a fairly complex IPTables setup which handles our gateways and internal hosts. My question is just how much effort is involved in moving these rules from IPv4 to IPv6? Are there elements in one that are not available in the other? Are there any fundamental incompatibilites? Does anyone have a good reference to a case history of moving from one to the other?

Regards,