I know we've kicked this around a few times in the past, but
I don't know what the current state of things is ---
An Overwhelmingly Large ISP has asked me what I know about
SPF record validation tools.
In the validation space we need extreme thoroughness:
1) a regexp that validates the ABNF on a purely syntactic level
2) a parser that tokenizes validated records and warns about
unrecognized mechanisms and modifiers.
3) a recursion follower that evaluates includes and redirects
4) an overall optimizer that recommends moving ip4
mechanisms ahead of other mechanisms, and so on
5) a validator for each mechanism that confirms that its
target is resolvable --- for example, given mx:foo.com,
we need to chase down each MX server for foo.com and all
of their hostnames. if any of their hostnames is
unresolvable, report an error.
I know that people are working on this, but I'm not sure
where things stand. I'd like to add fill out the
"certification" webpage on spf.pobox.com so could anyone
who's doing work in this area please offer a status report?
There are two functional goals, or deliverables, for this:
1) web page where you can paste in a proposed v=spf1 record
and see what the validator thinks
2) the same web page, but if you paste in a domain name it
fetches the record from DNS directly