RE: [Exim] AOL - SPF - and EXIM

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Author: Edgar Lovecraft
Date:  
To: 'exim-users@exim.org'
Subject: RE: [Exim] AOL - SPF - and EXIM
David Brodbeck wrote:
>
> > -----Original Message-----
> > From: Walt Reed [mailto:exim@linuxguy.com]
>
> > Will you please convince Verizon to do this? They will NOT set reverse
> > DNS with static IP addresses on Business DSL service, Period.
>
> I'm not aware of any ISPs that *will* set reverse DNS records for people
> with static IPs, unless you have a T1 or other premium service. I've
> been involved in setting up a few business-class DSL connections (/28s,
> mostly) and all of them stated in the terms of service that custom
> reverse DNS wasn't part of the deal.


Hmm, now that I think about it, any client that neede to change DNS PTR
records did have a 'premium' service, such as some point-to-point
lines, or frame circuits...

> About a decade ago, when Internet access was expensive, and always-on
> connections (or, in some areas, any connections at all) were solely the
> province of colleges and large companies, you could get that kind of
> personalized service from an ISP. Now it's a commodity, margins are
> slim, and they just don't deal with it anymore.


Some do, some don't. Those that don't will eventually lose the customers
thatneed both static addresses, and the ability to get the DNS PTR
records changed, note that I did not say 'control of', just changed :)

> I suppose you could always set your mailer to send an EHLO line that
> matches your reverse DNS. It would probably satisfy the DNS purists,
> but it wouldn't provide any useful information since you're not actually
> accepting mail for that domain.


It does provide usefull information. It provides usefull information
for that stage of the SMTP transaction. A proper HELO/EHLO string
allows the 'system' to be 'verified' as actually being the host they
say they are. The HELO/EHLO string has never had anything to do with
whether or not the system accepts email for any domain. That is where
a proper DNS name is used with the "MAIL FROM:" command. It would be
benifitial, and the suggested DNS setup should have proper PTR records,
but the domain given in the "MAIL FROM:" command tells us what machine,
A or MX record, accepts email for delivery, not the HELO/EHLO string.
They really have nothing to do with each other. All the HELO/EHLO
string does, is identify the connecting system, that is it.

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--EAL--