Reverse DNS issue rejected emails from Exchange Server

Posted on 2007-08-01
Last Modified: 2012-06-22
I have an issue with a small percentage of emails going out from our Exchange 2000 / SBS Server.

These are being bounced back with 554 5.7.1 <[xx.xx.xx.xx]>: Client host rejected: Access is not allowed>
(I obscured the ip address).

From research it seems that we do not have a valid Reverse DNS entry as this seems to point to our ISP Pipex and not to our domain name.
Am I right in thinking that some mailservers require the reverse DNS entry to match the sending domain name?
I have spoken to Pipex and they refused to set up Reverse DNS for us! So apparently the only option is to forward all mail through their SMTP server.

Is this correct ? If so, what are the implications of this and the fact that we don't have a valid reverse DNS at our company?

Question by:chrismanncalgavin
    1 Comment
    LVL 7

    Accepted Solution

    if you have an isp that wont setup reverse dns for you they are chumps and you should dump them before you have bigger problems with them.

    Yes you can use a smart host for all outgoing mail by pointing to their smtp server.  the primary implication in doing this is that you are relying on another 3rd party to make sure their stuff is working and configured correctly.

    Also, depending on what they do with the mails headers when they are relayed, it can sometimes be difficult to troubleshoot mail problems from the other end (if there are problems and if they do actually muck up the origination headers).

    All in all, it should work just fine.

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