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Re: External connection to Postfix problem

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  • Scott Kitterman
    ... I think it s stunningly unlikely that you are having an issue related to upstream Postfix issues. I would recommend using an Ubuntu server specific venue
    Message 1 of 5 , Jun 20, 2013
      On Thursday, June 20, 2013 10:19:25 AM Gary Brinker wrote:
      > Because of a hardware failure on an old installation of a postfix gateway I
      > took the opportunity to install an up to date version on an Ubuntu server.
      > I am not too far into the configuration but am having a basic problem with
      > accessing it from external sites. I think I can eliminate the usual DNS and
      > router configurations as it did work correctly with the old system. The
      > issue is that I can telnet into it internally with no problem but cannot
      > reach it externally. I hooked up wireshark and if I'm interpreting it
      > correctly I do find the initial SYN come in but no connection is
      > established. My reading suggests that I may have an ownership or
      > permissions problem, but I'm not finding success in isolating the issue.
      > Can anyone point out specifically what I should be looking at to diagnose
      > and correct this so I can get on to the meat of the configuration. Thanks
      > for any suggestions.

      I think it's stunningly unlikely that you are having an issue related to
      upstream Postfix issues. I would recommend using an Ubuntu server specific
      venue to try and fix the problem. One would be:

      https://lists.ubuntu.com/mailman/listinfo/ubuntu-server

      Scott K
    • Gary Brinker
      ... The output from the internal address is the 250 greeting banner and using the external IP is could not open connection : connection failed Gary
      Message 2 of 5 , Jun 20, 2013

         

        > Report the output from "telnet postfix-ip-address 25" from a
        > different machine on your local network.
        >
        > Wietse
         

        The output from the internal address is the 250 greeting banner and using the external IP is
        could not open connection : connection failed
         
        Gary
      • Wietse Venema
        ... This confirms that Postfix accepts network connections, and that the problem is outside of Postfix. It could be any of: - Incorrect default route
        Message 3 of 5 , Jun 20, 2013
          Wietse:
          > Report the output from "telnet postfix-ip-address 25" from a
          > different machine on your local network.

          Gary Brinker:
          > The output from the internal address is the 250 greeting banner
          > and using the external IP is could not open connection : connection
          > failed Gary

          This confirms that Postfix accepts network connections, and
          that the problem is outside of Postfix.

          It could be any of:
          - Incorrect default route configured on the Postfix host
          - Incorrect firewall configuration on the Postfix host
          - Incorrect LAN router configuration (NAT/forwarding)
          - Conflict with ISP-side configuration
          - ....

          This is a matter of systematic trouble shooting, or random experiments
          and dumb luck.

          Wietse
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