Re: TODO Item: Allow pg_hba.conf to specify host names along with IP addresses

On Fri, Jun 13, 2008 at 08:51:19PM +0100, Simon Riggs wrote:

> The best of both ideas would be to have an option inside pg_hab.conf to
> indicate when lookup occurs. Some parts of a network are static, others
> are not, so a global option would not be useful.

We would point and laugh at people who thought that something was
"static" inside PostgreSQL, and depended on that for something
critical without some pretty heavy-duty locks. Are we really
proposing to offer an authentication mechanism that depends on
something as flimsy as hostname lookups in the DNS, and then not
insist that the bare minimum of integrity check ("I checked this DNS
lookup at connection time") is the rule?

DNS is a distributed database. Surely the least we can demand is that
the lookup happen when the naive think it will (i.e., at the time the
connection from that hostname happens).

> If the user knows a portion of their network is static,

If there were the slightest evidence that users historically believed
in such "knowledge" correctly, then I might have some sympathy for
this. The fact is that DNS (at least without DNSSEC) is one of the
areas in which sysadmins have the worst record of trust to this day.
I think we'd be fools to encourage such trust. If you don't look up
at _least_ at connection time, this feature should be rejected on the
grounds that it opens a new authentication hole a mile wide.

A

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