Re: Why don't we allow DNS names in pg_hba.conf?

Added to TODO:

o Allow pg_hba.conf to specify host names along with IP addresses

Host name lookup could occur when the postmaster reads the
pg_hba.conf file, or when the backend starts. Another
solution would be to reverse lookup the connection IP and
check that hostname against the host names in pg_hba.conf.
We could also then check that the host name maps to the IP
address.

---------------------------------------------------------------------------

Tom Lane wrote:
> mark(at)mark(dot)mielke(dot)cc writes:
> > On Tue, Jan 03, 2006 at 12:43:03PM -0500, Tom Lane wrote:
> >> I'm not sure about the relative usefulness of this compared to the
> >> forward-lookup case, nor whether it's riskier or less risky from a
> >> spoofing point of view. But something to consider.
>
> > I think it's riskier. I have my own PTR records, that I can make be
> > whatever I wish without any authority verifying that my actions are
> > proper.
>
> Yeah, that occurred to me after a few moments' thought. We could do one
> extra forward lookup to confirm that the reverse-lookup name maps back
> to the IP address.
>
> > It's not a big deal.
>
> Depends on how many names you want to put into pg_hba.conf. I don't
> offhand see a use-case for very many, but maybe there is one. Even
> if there are a lot, they'd not be expensive to look up if there is
> a local nameserver that is authoritative for those names ... which
> I'd think would be the normal case. The more "outside" names you've
> got in pg_hba.conf, the more open you are to spoofing.
>
> regards, tom lane
>
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