David MacQuigg wrote:
Is there any reason not to set up subdomains like
_SPF1.<domain> ?
Discussed on mxcomp (the former MARID list) many times. One
problem is obvious, if you can do something with the records
for FQDN, it doesn't necessarily mean that you can also do
something with _SPF.FQDN And the DNS crowd hated the idea.
Another problem is less obvious, it doesn't work well with
wildcards. For almost all foobar.claranet.de (excl. names
like pop, www, and a few other exceptions) you get the same
wildcard policy as for xyzzy.claranet.de
Of course this also covers _SPF.foobar and _SPF.xyzzy, but
the potential advantage of the prefix is lost. Please check
the mxcomp archive for more details and better explanations.
when the query for _SPF1.<domain> arrives at <domain>, that
the nameserver at <domain> will be smart enough to return
the final result.
Servers aren't smart, they implement protocols if you're lucky.
Most of the time they only pretend to implement a protocol. ;-)
You'd get an authoritative answer from the NS for FQDN if you
ask for _SPF.FQDN. Test q=ns for _SPF.xyzzy.claranet.de and
then ask the NS.
Bye, Frank