Google "classless reverse dns delegation" and check out RFC 2317. The use
of CNAMEs is how this is accomplished when you only have a small block of
IP addresses. This is how any ISP we've ever dealt with has allowed us to
set PTR records. Many ISPs just don't want to deal with the hassles of
setting up and maintaining PTR records for all of their customers. The
thing to do is to get them hand off the resolution of those PTRs to your
own DNS server/provider. If they refuse (or can't figure out how) to do
that then I'd seriously consider finding another ISP.
----- Original Message -----
From: "N Parr" <[EMAIL PROTECTED]>
To: "NT System Admin Issues" <[email protected]>
Sent: Wednesday, May 28, 2008 11:53 AM
Subject: RE: Reverse DNS Advice for outbound email
That's exactly my concern and why I thought of it because I have my
filter set up the same way. Problem is I'm limited on my provider
choices. A CNAME record wouldn't work for this would it? From what
I've read it's a bad thing to mix MX with cnames.
-----Original Message-----
From: Micheal Espinola Jr [mailto:[EMAIL PROTECTED]
Sent: Wednesday, May 28, 2008 12:46 PM
To: NT System Admin Issues
Subject: Re: Reverse DNS Advice for outbound email
I would change providers. There are words in our PTR that can trigger
spam filters. Words like, "pool", etc... At least its not based on an
IP or MAC address, but its still a risk.
On Wed, May 28, 2008 at 1:38 PM, N Parr <[EMAIL PROTECTED]>
wrote:
We host our own email and we are changing our primary ISP. Per their
policy they will not change the Reverse DNS of our static IP to be
anything other than mortonrb-pool5-static-4.ispxxx.com. I have
control of my DNS records and can set that as an MX but I'm kind of
worried about some spam filters having issues with such a long DNS
name with the word "pool" in it when trying to send mail. Using their
mail server as a smart host is out of the question because if they go
down our ASA box will automatically fail over to our secondary ISP and
be unable to connect to their down mail server. Do you think using
this long DNS name will cause issues trying to send outbound email.
BTW my DNS is hosted with network solutions and they don't support TXT
records so I can't create an SPF.
Thanks
Niles
~ Upgrade to Next Generation Antispam/Antivirus with Ninja! ~
~ <http://www.sunbelt-software.com/SunbeltMessagingNinja.cfm> ~
--
ME2
~ Upgrade to Next Generation Antispam/Antivirus with Ninja! ~
~ <http://www.sunbelt-software.com/SunbeltMessagingNinja.cfm> ~
~ Upgrade to Next Generation Antispam/Antivirus with Ninja! ~
~ <http://www.sunbelt-software.com/SunbeltMessagingNinja.cfm> ~
~ Upgrade to Next Generation Antispam/Antivirus with Ninja! ~
~ <http://www.sunbelt-software.com/SunbeltMessagingNinja.cfm> ~
