Re: [cobalt-users] PTR Records

[flash22@xxxxxxx]

On Tue, 30 Jan 2001 baltimoremd@xxxxxxxxxxxxxxx wrote:

> I've been told by a RaQ4 owner with a large number of name-based sites
> that enabling PTR records in the RaQ DNS can cause problems.
> 
> Is that correct, or some type of Cobalt myth?

No, PTR records can cause problems if the PTR is a domain name that is
used as the target of an email address, sendmail will lookup the PTR and
rewrite the address, if there is a MX from that address back to the PTR
domain, then sendmail goees into spastic loops ;)

ex: mail.foo.com PTR foo.com
    foo.com MX mail.foo.com

will cause loops....(but using an A record for mail.foo.com makes
everything happy, even if it's IP is the same as the IP for foo.com)

You can use PTR's for other things fine however, there's nothing weird
about DNS on the raq, just a bit of touchiness with sendmail+virtual users

I would note however that the general rule for using PTR is that you use
it only when you can't possably use anything else ;)