Hi
I was hoping I could get some help.
Current Server set up is this. SBS2011, Exchange is used to send emails directly, however it receives emails from a POP connector, (The client prefers this method, although I am looking at tryiong to get it moved so Exchange handles everythign and will be asking for advice on that soon for backup of email when net is down)
We have had a bounce back on a spam filter for one of their contacts which says about the reverse DNS not matching, and this is the first time this has happened. This set up they had with SBS2008 and everything worked great for years. This is a new client contact they are having trouble with.
"E6:Mail
rejected because server_address does not match Reverse DNS."
during the delivery of this message to this e-mail address. Try sending this
message again. If the problem continues, please contact your
helpdesk.
So I am unsure why this has happened, and was hoping someone could give a pointer.
Essentially the system is this
the MX record is mail.domain.com - the ip of mail.domain.com is to the web server A.A.A.A where the mail is stored in pop boxes and the server then accesses to download.
The server IP is B.B.B.B, the Exchange server sends emails directly from itself to whoever.
The reverse DNS of B.B.B.B is mail.domain.com
For the past with any reverse DNS checkers this has worked great. It even passes all MXToolbox checks when smtp is tested against B.B.B.B
The only thing I can assume is that this client checks thoroughly that what is reverse of B.B.B.B - oh it is mail.domain.com.... so mail.domain.com is A.A.A.A oooh hang on A.A.A.A is not B.B.B.B this must be fake....
The SPF is set up fully to authorise A.A.A.A and B.B.B.B and the appropriate a records to send email on behalf of the domain.
Any ideas?
The only other thing I can think of is it is all dealing with IP6, as thats the only IP's mentioned in the email.... and nothing has beens et up with IP6, only the default settings??
Any help gratefully received
Tris