RE: DEPLOY: Over-running TXT dataspace in FQDN (-protocol I belie ve)

[Rand Wacker <rand@xxxxxxxxxxxx>]

Phillip brings up a very good point here because if the desire for
wildcards is to make it easy for sites to indicate where mail *does not*
come from for hosts under their domain, then this application is pretty
moot because every sane MTA on the planet /already/ rejects mail for this
there is no resolvable FQDN (why bother accepting a message if you know up
front you couldn't ever reply to it).

-Rand


On Thu, 26 Aug 2004, Hallam-Baker, Phillip wrote:

> While David is right, there is also the corollary that *.example.com
> will only match nodes that do not exist at all. So there are two issues,
> do wildcards work as expected, is the wildcard useful at all. The matching
> behavior means that the wildcard is not useful for the use cases given.
>
> i.e. if we have
>
> a.example.com
>
> *.example.com. IN TXT "v=spf1 ..."
>
> Will match _marid.b.example.com, b.example.com but not a.example.com
> regardless of whether a has TXT records or not.
>
> So you can't use a wildcard to give a default SPF record for DNS
> names of hosts that exist. Only the hosts that don't exist will match.
>
>
> I don't know what happens for _marid.a.example.com, I think it should
> not match but one of the DNS people can say for sure.
>
>
> IF _marid.a.example.com did match the wildcard then it would be a way
> to make the wildcards useful.
>
>
>