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Different SMTP hostname greeting for each IP Address

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  • Cameron Smith
    How can I set a different SMTP hostname greeting for each dedicated IP Address on my server? If my main SMTP hostname is: vps.example.com with the IP of
    Message 1 of 16 , Sep 29, 2011
      How can I set a different SMTP hostname greeting for each dedicated IP Address on my server?

      If my main SMTP hostname is:
      with the IP of 192.0.43.10

      and I have some vhosts on that server with dedicated IPs

      domainone.com  192.0.43.11
      domaintwo.com 192.0.43.12
      domainthree.com 192.0.43.13

      How can I make the SMTP hostname greeting for those IPs match the domains?

      I have reverse dns already set for this and now would like to find a way to have Postfix cover the greeting part.

      I found a tutorial online that mentioned editing master.cf to add this:


      192.0.43.11:smtp inet n - n - - smtpd -o myhostname=domainone.com
      192.0.43.12:smtp inet n - n - - smtpd -o myhostname=domaintwo.com
      192.0.43.13:smtp inet n - n - - smtpd -o myhostname=domainthree.com

      But I am not sure that is correct and wanted to ask here.
      My intention is to remove the unknown [192.0.43.11] in headers and make them look like domainone.com [192.0.43.11

      Thanks,
      Cameron
    • Viktor Dukhovni
      ... No need. ... This works to a degree, but you don t want this. ... The greeting name of the SMTP server is never recorded in message headers. Receiving
      Message 2 of 16 , Sep 29, 2011
        On Thu, Sep 29, 2011 at 12:25:07PM -0700, Cameron Smith wrote:

        > How can I set a different SMTP hostname greeting for each dedicated
        > IP Address on my server?
        >
        > domainone.com 192.0.43.11
        > domaintwo.com 192.0.43.12
        > domainthree.com 192.0.43.13
        >
        > How can I make the SMTP hostname greeting for those IPs match the domains?

        No need.

        > 192.0.43.11:smtp inet n - n - - smtpd -o myhostname=domainone.com
        > 192.0.43.12:smtp inet n - n - - smtpd -o myhostname=domaintwo.com
        > 192.0.43.13:smtp inet n - n - - smtpd -o myhostname=domainthree.com

        This works to a degree, but you don't want this.

        > But I am not sure that is correct and wanted to ask here.
        > My intention is to remove the unknown [192.0.43.11] in headers
        > and make them look like domainone.com [192.0.43.11]

        The greeting name of the SMTP server is never recorded in message
        headers. Receiving systems will record the DNS name associated with
        the outgoing client IP and the EHLO name sent by your Postfix SMTP client.

        If your IPs don't resolve (on the public internet) to PTRs that
        resolve back to the same names, fix that.

        --
        Viktor.
      • Cameron Smith
        ... Thank you for your reply Viktor! I am probably calling my question the wrong thing so I will give real world examples. In the email I am replying to one of
        Message 3 of 16 , Sep 29, 2011

          On Sep 29, 2011, at 12:36 PM, Viktor Dukhovni wrote:

          On Thu, Sep 29, 2011 at 12:25:07PM -0700, Cameron Smith wrote:

          How can I set a different SMTP hostname greeting for each dedicated
          IP Address on my server?

          domainone.com  192.0.43.11
          domaintwo.com 192.0.43.12
          domainthree.com 192.0.43.13

          How can I make the SMTP hostname greeting for those IPs match the domains?

          No need.

          192.0.43.11:smtp inet n - n - - smtpd -o myhostname=domainone.com
          192.0.43.12:smtp inet n - n - - smtpd -o myhostname=domaintwo.com
          192.0.43.13:smtp inet n - n - - smtpd -o myhostname=domainthree.com

          This works to a degree, but you don't want this.

          But I am not sure that is correct and wanted to ask here.
          My intention is to remove the unknown [192.0.43.11] in headers
          and make them look like domainone.com [192.0.43.11]

          The greeting name of the SMTP server is never recorded in message
          headers. Receiving systems will record the DNS name associated with
          the outgoing client IP and the EHLO name sent by your Postfix SMTP client.

          If your IPs don't resolve (on the public internet) to PTRs that
          resolve back to the same names, fix that.

          --
          Viktor.

          Thank you for your reply Viktor!

          I am probably calling my question the wrong thing so I will give real world examples.

          In the email I am replying to one of the headers was:

          Received: from mournblade.imrryr.org (mournblade.imrryr.org [208.77.212.107]) by russian-caravan.cloud9.net 


          See how mournblade.imrryr.org is listed in front of the IP?

          For my system would like the domain name listed there to be the domain that lives on that IP but the headers show:

          Received: from www.alwaysbuywholesale.com (unknown [74.63.3.132]) by vps.velvetpixel.net 


          Is this a DNS issue or a Postfix configuration issue?

          For my real world example I will give you my details to confirm if it DNS or not.

          server
          74.63.2.190

          domain with dedicated IP
          74.63.3.132

          The A record I control and it is set correctly:
          alwaysbuywholesale.com. 300 IN A 74.63.3.132

          The PTR is controlled my my provider and it returns:
          132.3.63.74.in-addr.arpa domain name pointer alwaysbuywholesale.com.

          My IP for the domain in question is resolving so why is unknown listed in the header?

          Cameron

        • Viktor Dukhovni
          ... The host russian-caravan.cloud9.net was able to resolve the IP address to a hostname which matched the IP. ... The host vps.velvetpixel.net was unable
          Message 4 of 16 , Sep 29, 2011
            On Thu, Sep 29, 2011 at 02:29:16PM -0700, Cameron Smith wrote:

            > >> How can I make the SMTP hostname greeting for those IPs match the domains?
            > >
            > > No need.
            > >
            > >> 192.0.43.11:smtp inet n - n - - smtpd -o myhostname=domainone.com
            > >> 192.0.43.12:smtp inet n - n - - smtpd -o myhostname=domaintwo.com
            > >> 192.0.43.13:smtp inet n - n - - smtpd -o myhostname=domainthree.com
            > >
            > > This works to a degree, but you don't want this.
            > >
            > > The greeting name of the SMTP server is never recorded in message
            > > headers. Receiving systems will record the DNS name associated with
            > > the outgoing client IP and the EHLO name sent by your Postfix SMTP client.
            > >
            > > If your IPs don't resolve (on the public internet) to PTRs that
            > > resolve back to the same names, fix that.

            > Received: from mournblade.imrryr.org (mournblade.imrryr.org [208.77.212.107]) by russian-caravan.cloud9.net

            The host "russian-caravan.cloud9.net" was able to resolve the IP address to
            a hostname which matched the IP.

            > For my system would like the domain name listed there to be the domain that lives on that IP but the headers show:
            > Received: from www.alwaysbuywholesale.com (unknown [74.63.3.132]) by vps.velvetpixel.net

            The host "vps.velvetpixel.net" was unable to resolve the IP address
            "74.63.3.132" to a hostname which matched the IP.

            > Is this a DNS issue or a Postfix configuration issue?

            DNS. You may want to set "smtp_helo_name=alwaysbuywholesale.com" since that's
            your system's name, but this has no effect on the "unknown" issue.

            Since the DNS data in question looks good to me, the issue is perhaps
            on the vps client, but perhaps things were different at the time message
            was sent, or not all your DNS servers return the same answer.

            --
            Viktor.
          • Cameron Smith
            ... Thanks Viktor :) What you said made me troubleshoot a little deeper and I found that the unknown was caused by not having the correct entry for that
            Message 5 of 16 , Sep 29, 2011
              On Sep 29, 2011, at 3:16 PM, Viktor Dukhovni wrote:

              > On Thu, Sep 29, 2011 at 02:29:16PM -0700, Cameron Smith wrote:
              >
              >>>> How can I make the SMTP hostname greeting for those IPs match the domains?
              >>>
              >>> No need.
              >>>
              >>>> 192.0.43.11:smtp inet n - n - - smtpd -o myhostname=domainone.com
              >>>> 192.0.43.12:smtp inet n - n - - smtpd -o myhostname=domaintwo.com
              >>>> 192.0.43.13:smtp inet n - n - - smtpd -o myhostname=domainthree.com
              >>>
              >>> This works to a degree, but you don't want this.
              >>>
              >>> The greeting name of the SMTP server is never recorded in message
              >>> headers. Receiving systems will record the DNS name associated with
              >>> the outgoing client IP and the EHLO name sent by your Postfix SMTP client.
              >>>
              >>> If your IPs don't resolve (on the public internet) to PTRs that
              >>> resolve back to the same names, fix that.
              >
              >> Received: from mournblade.imrryr.org (mournblade.imrryr.org [208.77.212.107]) by russian-caravan.cloud9.net
              >
              > The host "russian-caravan.cloud9.net" was able to resolve the IP address to
              > a hostname which matched the IP.
              >
              >> For my system would like the domain name listed there to be the domain that lives on that IP but the headers show:
              >> Received: from www.alwaysbuywholesale.com (unknown [74.63.3.132]) by vps.velvetpixel.net
              >
              > The host "vps.velvetpixel.net" was unable to resolve the IP address
              > "74.63.3.132" to a hostname which matched the IP.
              >
              >> Is this a DNS issue or a Postfix configuration issue?
              >
              > DNS. You may want to set "smtp_helo_name=alwaysbuywholesale.com" since that's
              > your system's name, but this has no effect on the "unknown" issue.
              >
              > Since the DNS data in question looks good to me, the issue is perhaps
              > on the vps client, but perhaps things were different at the time message
              > was sent, or not all your DNS servers return the same answer.
              >

              Thanks Viktor :)

              What you said made me troubleshoot a little deeper and I found that the "unknown" was caused by not having the correct entry for that domain and it's dedicated IP in my /etc/hosts file so that part is fixed!

              I am still running into the SMTP banner mismatch issue though.
              alwaysbuywholesale.com is not my system name. It is just a virtual host with a dedicated IP on my system. My system hostname is vps.velvetpixel.net and it's IP is 74.63.2.190

              When I run the test at mxtoolbox for the virtual host domain dedicated IP 74.63.3.132 I get the "Warning - Reverse DNS does not match SMTP Banner" error

              It displays the server's hostname:
              220 vps.velvetpixel.net ESMTP Postfix

              which is fine for all mail associated with the IP of the server but I still want to change the SMTP banners so that they match reverse for each different IP on the server. It seems like I am in a catch 22 for domains on additional dedicated IPs on my server where DNS A and PTR match but then I can't make the SMTP banner match the info for that vhost as it's stuck on the server hostname.

              All I want is general mail from domains without a dedicated IP to stay as:
              220 vps.velvetpixel.net ESMTP Postfix

              and domains with a dedicated IP such as alwaysbuywholesale.com to have this style:
              220 alwaysbuywholesale.com ESMTP Postfix

              Where alwaysbuywholesale.com is what matches PTR for that dedicated IP.

              Is this not possible?

              Thanks,
              Cameron
            • Wietse Venema
              ... $ host 74.63.3.132 132.3.63.74.in-addr.arpa domain name pointer alwaysbuywholesale.com. $ host -t a alwaysbuywholesale.com. alwaysbuywholesale.com has
              Message 6 of 16 , Sep 29, 2011
                Cameron Smith:
                > For my system would like the domain name listed there to be the
                > domain that lives on that IP but the headers show:
                > Received: from www.alwaysbuywholesale.com (unknown [74.63.3.132]) ....

                $ host 74.63.3.132
                132.3.63.74.in-addr.arpa domain name pointer alwaysbuywholesale.com.

                $ host -t a alwaysbuywholesale.com.
                alwaysbuywholesale.com has address 74.63.3.132

                Therefore, the SMTP client on 74.63.3.132 should announce itself
                as alwaysbuywholesale.com instead of www.alwaysbuywholesale.com.

                Wieste
              • Cameron Smith
                ... Thank you Weitse :) So if I change my PTR for that IP to www.alwaysbuywholesale.com I will no longer get the mismatch error? Also for reference where do I
                Message 7 of 16 , Sep 29, 2011
                  On Sep 29, 2011, at 5:48 PM, Wietse Venema wrote:

                  > Cameron Smith:
                  >> For my system would like the domain name listed there to be the
                  >> domain that lives on that IP but the headers show:
                  >> Received: from www.alwaysbuywholesale.com (unknown [74.63.3.132]) ....
                  >
                  > $ host 74.63.3.132
                  > 132.3.63.74.in-addr.arpa domain name pointer alwaysbuywholesale.com.
                  >
                  > $ host -t a alwaysbuywholesale.com.
                  > alwaysbuywholesale.com has address 74.63.3.132
                  >
                  > Therefore, the SMTP client on 74.63.3.132 should announce itself
                  > as alwaysbuywholesale.com instead of www.alwaysbuywholesale.com.
                  >
                  > Wieste

                  Thank you Weitse :)

                  So if I change my PTR for that IP to www.alwaysbuywholesale.com I will no longer get the mismatch error?

                  Also for reference where do I change how the SMTP client announces for the different IPs on the server?
                • Wietse Venema
                  ... There is no mis-match in the DNS lookups. Wietse
                  Message 8 of 16 , Sep 29, 2011
                    Cameron Smith:
                    >
                    > On Sep 29, 2011, at 5:48 PM, Wietse Venema wrote:
                    >
                    > > Cameron Smith:
                    > >> For my system would like the domain name listed there to be the
                    > >> domain that lives on that IP but the headers show:
                    > >> Received: from www.alwaysbuywholesale.com (unknown [74.63.3.132]) ....
                    > >
                    > > $ host 74.63.3.132
                    > > 132.3.63.74.in-addr.arpa domain name pointer alwaysbuywholesale.com.
                    > >
                    > > $ host -t a alwaysbuywholesale.com.
                    > > alwaysbuywholesale.com has address 74.63.3.132
                    > >
                    > > Therefore, the SMTP client on 74.63.3.132 should announce itself
                    > > as alwaysbuywholesale.com instead of www.alwaysbuywholesale.com.
                    > >
                    > > Wieste
                    >
                    > Thank you Weitse :)
                    >
                    > So if I change my PTR for that IP to www.alwaysbuywholesale.com
                    > I will no longer get the mismatch error?

                    There is no mis-match in the DNS lookups.

                    Wietse
                  • Cameron Smith
                    ... Viktor had already helped me fix the unknown issue. Here is an example Received header for a domain with a dedicated IP of 74.63.3.132 :) Received:
                    Message 9 of 16 , Oct 2, 2011

                      On Sep 29, 2011, at 7:07 PM, Wietse Venema wrote:

                      Cameron Smith:

                      On Sep 29, 2011, at 5:48 PM, Wietse Venema wrote:

                      Cameron Smith:
                      For my system would like the domain name listed there to be the
                      domain that lives on that IP but the headers show:
                      Received: from www.alwaysbuywholesale.com (unknown [74.63.3.132]) ....

                      $ host 74.63.3.132
                      132.3.63.74.in-addr.arpa domain name pointer alwaysbuywholesale.com.

                      $ host -t a alwaysbuywholesale.com.
                      alwaysbuywholesale.com has address 74.63.3.132

                      Therefore, the SMTP client on 74.63.3.132 should announce itself
                      as alwaysbuywholesale.com instead of www.alwaysbuywholesale.com.

                      Wieste

                      Thank you Weitse :)

                      So if I change my PTR for that IP to  www.alwaysbuywholesale.com
                      I will no longer get the mismatch error?

                      There is no mis-match in the DNS lookups.

                      Wietse

                      Viktor had already helped me fix the "unknown" issue.

                      Here is an example Received header  for a domain with a dedicated IP of 74.63.3.132  :)

                      Received:  from www.alwaysbuywholesale.com (www.alwaysbuywholesale.com [74.63.3.132]) by vps.velvetpixel.net


                      The mismatch issue I mentioned I am still trying to solve is:

                      server
                      74.63.2.190

                      telnet 74.63.2.190 smtp
                      Trying 74.63.2.190...
                      Connected to vps.velvetpixel.net.
                      Escape character is '^]'.
                      220 vps.velvetpixel.net ESMTP Postfix   <-- this is s match!!!

                      virtual host with dedicated IP
                      74.63.3.132

                      telnet 74.63.3.132 smtp
                      Trying 74.63.3.132...
                      Connected to alwaysbuywholesale.com.
                      Escape character is '^]'.
                      220 vps.velvetpixel.net ESMTP Postfix  <--This is not a match :(

                      How do I change the SMTP banner for just the vhost dedicated IP 74.63.3.132 to 220 www.alwaysbuywholesale.com ESMTP Postfix   and still keep the correct banner of 220 vps.velvetpixel.net ESMTP Postfix for 74.63.2.190?

                      I can update my PTR for 74.63.3.132 so it is www.alwaysbuywholesale.com instead of alwaysbuywholesale.com but how do I change the banner for that dedicated IP so it then matches www.alwaysbuywholesale.com?

                      Cameron

                    • Sahil Tandon
                      ... Set an alternative smtpd_banner for the smtpd(8) listener on 74.63.3.132. -- Sahil Tandon
                      Message 10 of 16 , Oct 2, 2011
                        On Sun, 2011-10-02 at 10:29:20 -0700, Cameron Smith wrote:

                        > telnet 74.63.3.132 smtp
                        > Trying 74.63.3.132...
                        > Connected to alwaysbuywholesale.com.
                        > Escape character is '^]'.
                        > 220 vps.velvetpixel.net ESMTP Postfix <--This is not a match :(
                        >
                        > How do I change the SMTP banner for just the vhost dedicated IP
                        > 74.63.3.132 to 220 www.alwaysbuywholesale.com ESMTP Postfix and
                        > still keep the correct banner of 220 vps.velvetpixel.net ESMTP Postfix
                        > for 74.63.2.190?

                        Set an alternative smtpd_banner for the smtpd(8) listener on
                        74.63.3.132.

                        --
                        Sahil Tandon
                      • Cameron Smith
                        ... How do I do that? Cameron
                        Message 11 of 16 , Oct 2, 2011
                          On Oct 2, 2011, at 11:59 AM, Sahil Tandon wrote:

                          > On Sun, 2011-10-02 at 10:29:20 -0700, Cameron Smith wrote:
                          >
                          >> telnet 74.63.3.132 smtp
                          >> Trying 74.63.3.132...
                          >> Connected to alwaysbuywholesale.com.
                          >> Escape character is '^]'.
                          >> 220 vps.velvetpixel.net ESMTP Postfix <--This is not a match :(
                          >>
                          >> How do I change the SMTP banner for just the vhost dedicated IP
                          >> 74.63.3.132 to 220 www.alwaysbuywholesale.com ESMTP Postfix and
                          >> still keep the correct banner of 220 vps.velvetpixel.net ESMTP Postfix
                          >> for 74.63.2.190?
                          >
                          > Set an alternative smtpd_banner for the smtpd(8) listener on
                          > 74.63.3.132.
                          >
                          > --
                          > Sahil Tandon

                          How do I do that?

                          Cameron
                        • Sahil Tandon
                          ... In master.cf, where you (presumably) setup the smtpd(8) instance that listens on 74.63.3.132. See: http://www.postfix.org/postconf.5.html#smtpd_banner
                          Message 12 of 16 , Oct 2, 2011
                            On Sun, 2011-10-02 at 12:34:41 -0700, Cameron Smith wrote:

                            > On Oct 2, 2011, at 11:59 AM, Sahil Tandon wrote:
                            >
                            > > On Sun, 2011-10-02 at 10:29:20 -0700, Cameron Smith wrote:
                            > >
                            > >> telnet 74.63.3.132 smtp
                            > >> Trying 74.63.3.132...
                            > >> Connected to alwaysbuywholesale.com.
                            > >> Escape character is '^]'.
                            > >> 220 vps.velvetpixel.net ESMTP Postfix <--This is not a match :(
                            > >>
                            > >> How do I change the SMTP banner for just the vhost dedicated IP
                            > >> 74.63.3.132 to 220 www.alwaysbuywholesale.com ESMTP Postfix and
                            > >> still keep the correct banner of 220 vps.velvetpixel.net ESMTP Postfix
                            > >> for 74.63.2.190?
                            > >
                            > > Set an alternative smtpd_banner for the smtpd(8) listener on
                            > > 74.63.3.132.
                            >
                            > How do I do that?

                            In master.cf, where you (presumably) setup the smtpd(8) instance that
                            listens on 74.63.3.132. See:

                            http://www.postfix.org/postconf.5.html#smtpd_banner
                            http://www.postfix.org/master.5.html

                            --
                            Sahil Tandon
                          • Wietse Venema
                            ... It may be easiest to append -o myhostname=www.alwaysbuywholesale.com to the master.cf line for 74.63.3.132. In main.cf, be sure to list
                            Message 13 of 16 , Oct 2, 2011
                              Sahil Tandon:
                              > On Sun, 2011-10-02 at 12:34:41 -0700, Cameron Smith wrote:
                              >
                              > > On Oct 2, 2011, at 11:59 AM, Sahil Tandon wrote:
                              > >
                              > > > On Sun, 2011-10-02 at 10:29:20 -0700, Cameron Smith wrote:
                              > > >
                              > > >> telnet 74.63.3.132 smtp
                              > > >> Trying 74.63.3.132...
                              > > >> Connected to alwaysbuywholesale.com.
                              > > >> Escape character is '^]'.
                              > > >> 220 vps.velvetpixel.net ESMTP Postfix <--This is not a match :(
                              > > >>
                              > > >> How do I change the SMTP banner for just the vhost dedicated IP
                              > > >> 74.63.3.132 to 220 www.alwaysbuywholesale.com ESMTP Postfix and
                              > > >> still keep the correct banner of 220 vps.velvetpixel.net ESMTP Postfix
                              > > >> for 74.63.2.190?
                              > > >
                              > > > Set an alternative smtpd_banner for the smtpd(8) listener on
                              > > > 74.63.3.132.
                              > >
                              > > How do I do that?
                              >
                              > In master.cf, where you (presumably) setup the smtpd(8) instance that
                              > listens on 74.63.3.132. See:
                              >
                              > http://www.postfix.org/postconf.5.html#smtpd_banner
                              > http://www.postfix.org/master.5.html

                              It may be easiest to append

                              -o myhostname=www.alwaysbuywholesale.com

                              to the master.cf line for 74.63.3.132.

                              In main.cf, be sure to list www.alwaysbuywholesale.com among the names
                              in mydestination.

                              Wietse
                            • Cameron Smith
                              ... Awesome :) Thank you Wietse!!!! Have a good evening, Cameron
                              Message 14 of 16 , Oct 2, 2011
                                On Oct 2, 2011, at 5:28 PM, Wietse Venema wrote:

                                > Sahil Tandon:
                                >> On Sun, 2011-10-02 at 12:34:41 -0700, Cameron Smith wrote:
                                >>
                                >>> On Oct 2, 2011, at 11:59 AM, Sahil Tandon wrote:
                                >>>
                                >>>> On Sun, 2011-10-02 at 10:29:20 -0700, Cameron Smith wrote:
                                >>>>
                                >>>>> telnet 74.63.3.132 smtp
                                >>>>> Trying 74.63.3.132...
                                >>>>> Connected to alwaysbuywholesale.com.
                                >>>>> Escape character is '^]'.
                                >>>>> 220 vps.velvetpixel.net ESMTP Postfix <--This is not a match :(
                                >>>>>
                                >>>>> How do I change the SMTP banner for just the vhost dedicated IP
                                >>>>> 74.63.3.132 to 220 www.alwaysbuywholesale.com ESMTP Postfix and
                                >>>>> still keep the correct banner of 220 vps.velvetpixel.net ESMTP Postfix
                                >>>>> for 74.63.2.190?
                                >>>>
                                >>>> Set an alternative smtpd_banner for the smtpd(8) listener on
                                >>>> 74.63.3.132.
                                >>>
                                >>> How do I do that?
                                >>
                                >> In master.cf, where you (presumably) setup the smtpd(8) instance that
                                >> listens on 74.63.3.132. See:
                                >>
                                >> http://www.postfix.org/postconf.5.html#smtpd_banner
                                >> http://www.postfix.org/master.5.html
                                >
                                > It may be easiest to append
                                >
                                > -o myhostname=www.alwaysbuywholesale.com
                                >
                                > to the master.cf line for 74.63.3.132.
                                >
                                > In main.cf, be sure to list www.alwaysbuywholesale.com among the names
                                > in mydestination.
                                >
                                > Wietse

                                Awesome :)

                                Thank you Wietse!!!!

                                Have a good evening,
                                Cameron
                              • Benny Pedersen
                                ... [snip] ... this is the way to make it yes just missing if you like it to be outgoing you still need to define smtp_helo_name= for smtp in master aswell
                                Message 15 of 16 , Oct 3, 2011
                                  On Thu, 29 Sep 2011 12:25:07 -0700, Cameron Smith wrote:
                                  > How can I set a different SMTP hostname greeting for each dedicated
                                  > IP
                                  > Address on my server?

                                  [snip]
                                  > 192.0.43.11:smtp inet n - n - - smtpd -o myhostname=domainone.com
                                  > 192.0.43.12:smtp inet n - n - - smtpd -o myhostname=domaintwo.com
                                  > 192.0.43.13:smtp inet n - n - - smtpd -o myhostname=domainthree.com
                                  >
                                  > But I am not sure that is correct and wanted to ask here.

                                  this is the way to make it yes

                                  just missing if you like it to be outgoing you still need to define

                                  smtp_helo_name= for smtp in master aswell
                                • Benny Pedersen
                                  ... isp issue, ask them to set PTR dns for your reverse dns, most isp will if you add a A record with same name
                                  Message 16 of 16 , Oct 3, 2011
                                    On Thu, 29 Sep 2011 14:29:16 -0700, Cameron Smith wrote:
                                    > RECEIVED: from www.alwaysbuywholesale.com (unknown [74.63.3.132])
                                    > by vps.velvetpixel.net
                                    >
                                    > Is this a DNS issue or a Postfix configuration issue?

                                    isp issue, ask them to set PTR dns for your reverse dns, most isp will
                                    if you add a A record with same name
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