Mailing List Archive

wizard setup
not sure i understand "ptr" question on wizard....is there help
somewhere...
we have two domain names that could be used for our IP address...
the question is not clear concerning "any host whose name ends in ..."
the answer is yes if it matches our IP number, which I think is what
they're asking???

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Re: wizard setup [ In reply to ]
I have wondered about that question too. But what ptr does is, if your
mailserver with ip 1.2.3.4 saying to be mydomain.com connects to a receiving
server then the receiving server will look up the reverse PTR records
for 1.2.3.4.

For each PTR result (which is a hostname) that ends with mydomain.com it
does an A lookup, and if this A lookup results in 1.2.3.4 again, the
result is PASS.

Also, have a look at http://spf.pobox.com/mechanisms.html#ptr

If you have two domain names, and just one IP address that acts as an
outgoing SMTP server for those two domains, publishing 'v=spf1 a:1.2.3.4
-all' or 'v=spf1 a:1.2.3.4 ~all' for both domains suffices. Note that
for other (sub-)domains you will probably also want to specify spf
records. Eg, if there's an A record for www.mydomain.com, be sure to
specify something like 'v=spf1 -all' (if of course, you never intend to
send mail with a MAIL FROM of www.mydomain.com).

Hope this helps,

Koen


On Tue, Jul 20, 2004 at 12:49:37PM -0500, RAY JEFFREYS wrote:
> not sure i understand "ptr" question on wizard....is there help
> somewhere...
> we have two domain names that could be used for our IP address...
> the question is not clear concerning "any host whose name ends in ..."
> the answer is yes if it matches our IP number, which I think is what
> they're asking???
>
> -------
> Archives at http://archives.listbox.com/spf-help/current/
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