Duane Hill:
> A quick search on the web I found this for IPv6 (all on one line):
>
> /^(((?=(?>.*?::)(?!.*::)))(::)?(([0-9A-F]{1,4})::?){0,5}|((?5):){6})(\2((?5)(::?
> |$)){0,2}|((25[0-5]|(2[0-4]|1[0-9]|[1-9])?[0-9])(\.|$)){4}|(?5):(?5))(?<![^:]:|\
> .)\z/i
That may be overkill.
While looking up the remote SMTP client hostname, Postfix enforces
proper domain name syntax (well almost - it allows "_" in hostnames).
Names that don't satisfy the rule are treated as "unknown".
Thus, for check_client_access table lookups, Postfix does the
following queries:
- A domain name (which never contains ":"), and perhaps suffixes
of the domain.
- An IPv4 address (which never contains ":"), and perhaps prefixes
of the address.
- An IPv6 address (which always contains ":"), and perhaps prefixes
of the addres.
Some table types such as CIDR ignore the domain name. With table
types such as CIDR, regexp and pcre, check_client_access does no
prefix/suffix lookups.
Given this, a pcre rule with ``/:/ DUNNO'' is sufficient to skip
IPv6 addresses.
Wietse
