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Problem telnet postfix from a network segment not local

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  • Cimoni Enwis Ogwujiakwu
    Hello I am having problem send mails from a client(not on a segment local to postfix server)  connected  to a postfix server on port 25. I tried
    Message 1 of 5 , Aug 31, 2010
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      Hello
      I am having problem send mails from a client(not on a segment local to postfix server)  connected  to a postfix server on port 25.
      I tried telnetting the post fix server on telnet 192.168.20.19 25 and I get the following
      Could not open connection to the host, on port 25: Connect failed
      Please help as this was working before and now it has stopped working.


      Cimoni Enwis Ogwujiakwu

    • Ansgar Wiechers
      ... If the IP address of the server hasn t changed and Postfix is still listening on port 25/tcp (check with ipconfig and netstat on the Postfix server), then
      Message 2 of 5 , Aug 31, 2010
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        On 2010-08-31 Cimoni Enwis Ogwujiakwu wrote:
        > I am having problem send mails from a client(not on a segment local to
        > postfix server) connected to a postfix server on port 25.
        > I tried telnetting the post fix server on telnet 192.168.20.19 25 and
        > I get the following
        > Could not open connection to the host, on port 25: Connect failed

        If the IP address of the server hasn't changed and Postfix is still
        listening on port 25/tcp (check with ipconfig and netstat on the Postfix
        server), then something between your client and the Postfix server is
        blocking connections to the Postfix server. tcptraceroute may help
        narrowing down that something.

        Regards
        Ansgar Wiechers
        --
        "Abstractions save us time working, but they don't save us time learning."
        --Joel Spolsky
      • Cimoni Enwis Ogwujiakwu
        netstat returned below which means server is listening on the port 25 and the IP address is still same 192.168.20.19 from ifconfig -a and still I cannot
        Message 3 of 5 , Sep 2, 2010
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          netstat returned below which means server is listening on the port 25 and the IP address is still same 192.168.20.19 from ifconfig -a and still I cannot connect on port 25. What do I do now?
          tcp4       0      0 *.25                   *.*                    LISTEN

          Cimoni Enwis Ogwujiakwu

          --- On Tue, 8/31/10, Ansgar Wiechers <lists@...> wrote:

          From: Ansgar Wiechers <lists@...>
          Subject: Re: Problem telnet postfix from a network segment not local
          To: postfix-users@...
          Date: Tuesday, August 31, 2010, 11:15 PM

          On 2010-08-31 Cimoni Enwis Ogwujiakwu wrote:
          > I am having problem send mails from a client(not on a segment local to
          > postfix server) connected to a postfix server on port 25.
          > I tried telnetting the post fix server on telnet 192.168.20.19 25 and
          > I get the following
          > Could not open connection to the host, on port 25: Connect failed

          If the IP address of the server hasn't changed and Postfix is still
          listening on port 25/tcp (check with ipconfig and netstat on the Postfix
          server), then something between your client and the Postfix server is
          blocking connections to the Postfix server. tcptraceroute may help
          narrowing down that something.

          Regards
          Ansgar Wiechers
          --
          "Abstractions save us time working, but they don't save us time learning."
          --Joel Spolsky


        • Ansgar Wiechers
          Please don t top-post. ... Good, so your Postfix instance is still listening on 192.168.20.19:25, meaning that it s most likely a network issue. ... Like I
          Message 4 of 5 , Sep 2, 2010
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            Please don't top-post.

            On 2010-09-02 Cimoni Enwis Ogwujiakwu wrote:
            > netstat returned below which means server is listening on the port 25
            > and the IP address is still same 192.168.20.19 from ifconfig -a

            Good, so your Postfix instance is still listening on 192.168.20.19:25,
            meaning that it's most likely a network issue.

            > and still I cannot connect on port 25. What do I do now?

            Like I said: use tcptraceroute to narrow down whatever it is that blocks
            the connection from your source host to your Postfix server.

            tcptraceroute -n 192.168.20.19 25

            Are both hosts on private IP address ranges?

            Regards
            Ansgar Wiechers
            --
            "Abstractions save us time working, but they don't save us time learning."
            --Joel Spolsky
          • Octavio
            Hello with smtpd_recipient_limit I can limit the number of recipients in a email that I send using the server who has that parameter configured., but how I can
            Message 5 of 5 , Sep 2, 2010
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              Hello
              with smtpd_recipient_limit I can limit the number of recipients in a email that I send using the server who has that parameter configured.,
              but how I can block the message that has more that X emails as TO:  in the header when they are sent by other server and Im receiving

              Thanks

              Octavio

               
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