i supose your could cheat and send your self an email from their
server and see what machines it goes though. that way you would have
the real ips, or at least, thats a theory!
Thanks for all your help!
On Fri, 4 Jun 2004 10:27:52 +0100, Peter Bowyer <peter(_at_)bowyer(_dot_)org>
wrote:
Michael R. Brumm <me(_at_)michaelbrumm(_dot_)com> wrote:
and if im using my isp's mail server, i just put that in as the ip?
hmmmm. my isp wont give me a PTR. so, im kind of screwed...
If they only give you an IP address (not a host name), then use it.
But ideally you wouldn't use an IP address because they might change
that (move the server to a different subnet due to security or
management reasons). If you are relaying through a host name like
"smtp.ntl.com", then this would be best:
"v=spfv1 a:smtp.ntl.com -all"
That's OK as long as the internet-facing 'outbound' IP(s) for the relay are
the same ones as the customer-facing 'inbound' IP(s) - I know some ISPs
where this wouldn't be the case - there's a hop from one set of MTAs to
another before the mail reaches the outside world.
The really safe thing to do would be to ask ntl what IP address(es) your
email will originate from if you use their mail relay. But I bet you'll have
difficulty finding the answer.
Peter
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