My understanding is that mx mechanism's shouldn't include IP
addresses:
1. Since MX names must be domain names anyway, and
2. since in the context of spf, it doesn't make sense for IP's
to be listed under "mx:" as opposed to "ip4:" or "ip6", and
3. since the spec does refer to the right-hand-side being
a domain-spec.
Is this correct?
The reason I ask is because of:
$ host -t txt advanta.com
advanta.com text "v=spf1 mx ptr mx:12.40.127.100 mx:12.40.127.108 ~all"
Given that the two ip's listed are their mx hosts, it looks like they
could just as well use "v=spf1 mx ptr ~all"
or even "v=spf1 ip4:12.40.127.100 ip4:12.40.127.108 ptr ~all".
Just wanted a sanity check first before I contacted them.
--
Mark Shewmaker
mark(_at_)primefactor(_dot_)com