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Outgoing mail, internal hostname

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  • Outgoing mail, internal hostname

    Typically I have Exchange forward mail via the ISP's SMTP server. But I have a site where the ISP doesn't allow you to relay mail via their server. This means Exchange now has to send directly. This isn't an issue but is an issue for companies who use advanced anti-spam technology.

    The server is advertising its internal IP and hostname on outgoing emails. Is there anywhere I can change this? I've been looking for an answer to this for many years but never actually found one.
    Please remember to leave positive reputation points (The Ying Yang Icon) if someone helps you.

  • #2
    Re: Outgoing mail, internal hostname

    On the Advanced buuton of the Delivery tab of the properties of the SMTP protocol in ESM set the FQDN to match the FQDN of your public MX record and make sure their is a public Reverse DNS record for the public ip of the host that your MX record points to. Your server will announce itself as the FQDN and as long as it matches your MX you should be OK. As far as advertising it's internal ip, that's OK as that's what all mail servers do when they connect and shouldn't cause any type of spam trigger. As long as the FQDN "announcement" from your server matches your public MX, and as long as the A and PTR records of the public ip your Exchange server is NAt'ed to match up you should be fine.

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    • #3
      Re: Outgoing mail, internal hostname

      The reverse DNS brings up the ISP's record which looks like it can't be changed.
      Please remember to leave positive reputation points (The Ying Yang Icon) if someone helps you.

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      • #4
        Re: Outgoing mail, internal hostname

        Is it something like: isp_host_ip.isp.com? You'll probably need to speak to them about creating a PTR record for the FQDN ip of the NAT'ed Exchange server ip address.

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        • #5
          Re: Outgoing mail, internal hostname

          Yes and its BT... who (are the biggest name in communications in the UK, acutally have the worst communications you can think of). I am not sure even then they would allow me to change my DNS record. I know with another ISP we can.
          Please remember to leave positive reputation points (The Ying Yang Icon) if someone helps you.

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          • #6
            Re: Outgoing mail, internal hostname

            I would advise you move the hosting of your domain to a hosting company and use your ISP as an ISP. ISPs are notorious for lousy service when it comes to domain hosting. Shop around and you'll find a company offering you hosting of your domain, with full DNS control, for peanuts.
            Gareth Howells

            BSc (Hons), MBCS, MCP, MCDST, ICCE

            Any advice is given in good faith and without warranty.

            Please give reputation points if somebody has helped you.

            "For by now I could have stretched out my hand and struck you and your people with a plague that would have wiped you off the Earth." (Exodus 9:15) - I could kill you with my thumb.

            "Everything that lives and moves will be food for you." (Genesis 9:3) - For every animal you don't eat, I'm going to eat three.

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            • #7
              Re: Outgoing mail, internal hostname

              The domain isn't hosted by the ISP. Reverse DNS is offered by the ISP not by a domain hosting company...
              Please remember to leave positive reputation points (The Ying Yang Icon) if someone helps you.

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              • #8
                Re: Outgoing mail, internal hostname

                Ask the question of BT first of all. They may allow you to add the PTR record. Joe Qwerty gives good advice below and your not entirely sure whether BT will or not, so best not to assume or doubt until you know. Good luck with it.

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                • #9
                  Re: Outgoing mail, internal hostname

                  Looks like they might be able to help me out. Not as easy as other ISP's but at least I don't have to ring their awful tech support line.
                  Please remember to leave positive reputation points (The Ying Yang Icon) if someone helps you.

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                  • #10
                    Re: Outgoing mail, internal hostname

                    Good to hear. Thanks for the link as well and the feedback.

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                    • #11
                      Re: Outgoing mail, internal hostname

                      Just an update:

                      Thank you for your request for reverse DNS

                      Request has been submitted- process time within 48 hours:- mail.xxxxxxx.com. xxx.xxx.xxx.xxx
                      ref xxxxxxx-xxxxx

                      Kind regards,
                      BT Business Support
                      I think this is the fastest and positive response I've ever had from BT!

                      Please remember to leave positive reputation points (The Ying Yang Icon) if someone helps you.

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                      • #12
                        Re: Outgoing mail, internal hostname

                        Just to clear up one thing - the presence of your internal IP address and server name in the headers is not the cause of email being blocked. Antispam features do not look at that deep. If they did they would block an awful lot of email. Take a look at the headers of Gmail - it bounces through at least two 10.x.x.x IPs before hitting the internet.

                        The only thing that antispam measures are looking at is what is connecting to them. The last link. If that is announcing itself with an internal name then that will be the cause of a problem, but that is easily fixed with Exchange 2007 by adjusting the FQDN value on the Send Connector.

                        Simon.
                        --
                        Simon Butler
                        Exchange MVP

                        Blog: http://blog.sembee.co.uk/
                        More Exchange Content: http://exchange.sembee.info/
                        Exchange Resources List: http://exbpa.com/
                        In the UK? Hire me: http://www.sembee.co.uk/

                        Sembee is a registered trademark, used here with permission.

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                        • #13
                          Re: Outgoing mail, internal hostname

                          Right, I should have been more specific. When your server issues the HELO command it does so with the FQDN you have configured. That's why it's important to set the correct FQDN on the server that matches your public MX record and to have a valid public A and PTR records for the FQDN.

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                          • #14
                            Re: Outgoing mail, internal hostname

                            First off, thanks for the help. The mail server now has a FQDN and it's configured properly in Exchange.

                            If I telnet to port 25 it now shows the FQDN and not the internal hostname. Outgoing mail also shows the correct information in the headers.

                            There is one line that bothers me though. Maybe you can tell me if its ok or not. This sits below a simular line which has the now correct FQDN information...
                            from sv001.domain.local ([10.50.0.200]) by sv001.domain.local ([10.50.0.200]) with mapi; Tue, 10 Feb 2009 09:09:02 +0000
                            This line to me is just saying that the server had picked up the mail from my mail client via MAPI. I guess its ok to have this there?
                            Please remember to leave positive reputation points (The Ying Yang Icon) if someone helps you.

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                            • #15
                              Re: Outgoing mail, internal hostname

                              You can't do anything with the line, so ignore it.

                              Simon.
                              --
                              Simon Butler
                              Exchange MVP

                              Blog: http://blog.sembee.co.uk/
                              More Exchange Content: http://exchange.sembee.info/
                              Exchange Resources List: http://exbpa.com/
                              In the UK? Hire me: http://www.sembee.co.uk/

                              Sembee is a registered trademark, used here with permission.

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