Yes, it most definitely does. Like Bruce stated, if you send an email to me, I am going to run a plethora of tests to determine if that email is legit, ham, spam or malicious. Those tests not only check the email itself, but also check the server it came from, the domain it came from, the IP it came from and so forth. So, if your sending server does not have a rDNS that is going to fail one or more tests. If it does not have a correctly formatted rDNS it is going to fail one or more tests. John T From: exchangelist-bounce@xxxxxxxxxxxxx [mailto:exchangelist-bounce@xxxxxxxxxxxxx] On Behalf Of Christine Allen Sent: Friday, October 26, 2007 7:42 AM To: exchangelist@xxxxxxxxxxxxx Subject: [ExchangeList] Re: Reverse DNS Look-up and Mail Thanks, I got one response that says it should not be affect, and one that says it should. Does anyone else want to weigh in? Regards, Christine Allen, MCSE Engineer II MicroData Group, Inc. 100 Cummings Center, Suite 146N Beverly, MA 01915 Voice 978.921.0990 x234 Fax 978.921.0950 <http://www.microdata.com> http://www.microdata.com cid:image001.jpg@01C7D34E.69167DE0 From: exchangelist-bounce@xxxxxxxxxxxxx [mailto:exchangelist-bounce@xxxxxxxxxxxxx] On Behalf Of Bruce J. Rose Sent: Friday, October 26, 2007 10:43 AM To: exchangelist@xxxxxxxxxxxxx Subject: [ExchangeList] Re: Reverse DNS Look-up and Mail Yes it does, because I cannot do a reverse lookup to verify it is coming from you it would get rejected as spam _____ From: exchangelist-bounce@xxxxxxxxxxxxx [mailto:exchangelist-bounce@xxxxxxxxxxxxx] On Behalf Of Christine Allen Sent: Friday, October 26, 2007 9:45 AM To: exchangelist@xxxxxxxxxxxxx Subject: RE: [ExchangeList] Re: Reverse DNS Look-up and Mail Thanks. Does this also affect if they can send mail to you? For example, I send you a message at the correct email address, but it gets bounced back to me. Regards, Christine Allen, MCSE Engineer II MicroData Group, Inc. 100 Cummings Center, Suite 146N Beverly, MA 01915 Voice 978.921.0990 x234 Fax 978.921.0950 <https://obiwan.microdata.com/exchweb/bin/redir.asp?URL=http://www.microdata .com> http://www.microdata.com _____ From: exchangelist-bounce@xxxxxxxxxxxxx on behalf of Michael B. Smith Sent: Fri 10/26/2007 9:37 AM To: exchangelist@xxxxxxxxxxxxx Subject: [ExchangeList] Re: Reverse DNS Look-up and Mail If you are sending e-mail from an IP address, you are pretty much required to set rDNS these days. Otherwise, the big boys (AOL, Yahoo, others) will not accept e-mail from you. Not to mention that some of the little guys won't either (like me - I've only got a few 10's of thousands of e-mail addresses). From: exchangelist-bounce@xxxxxxxxxxxxx [mailto:exchangelist-bounce@xxxxxxxxxxxxx] On Behalf Of Christine Allen Sent: Friday, October 26, 2007 9:28 AM To: exchangelist@xxxxxxxxxxxxx Subject: [ExchangeList] Reverse DNS Look-up and Mail Just a question. How many folks out there have reverse DNS lookup set-up for their domains to support mail? Regards, Christine Allen, MCSE Engineer II MicroData Group, Inc. 100 Cummings Center, Suite 146N Beverly, MA 01915 Voice 978.921.0990 x234 Fax 978.921.0950 <https://obiwan.microdata.com/exchweb/bin/redir.asp?URL=http://www.microdata .com> http://www.microdata.com