We support IPv4 and IPv6 address families, dual stack systems can filter on both
inet denotes IPv4 traffic
inet6 denotes IPv6 traffic
pass inet proto tcp port $ipv4services from $ipv4clients
pass inet6 proto tcp port $ipv6services from $ipv6clients(add appropriate macro definitions)
Note: on dual-stack systems, rules with no address family specified will match both AFs
In OpenBSD 5.1 onwards, we have Nat64 via af-to