postfix will not accept connection on port 25

started at 06 Feb 2011 by seventhfire
  • seventhfire
    06 Feb 2011

    I'm running pretty much the default install of postfix that comes with Snow Leopard. I can send mail out to the internet in a terminal on the system in question using mail or telnet to port 25 using localhost or the ip on the system.
    The problem I'm having is no other systems on my local network can get a connection to port 25.
    I've verified with netstat there is a process listening on port 25. I've setup mynetworks in include all ip's on my local network. I've made multiple searches on different forum's trying to figure this out but I'm missing the boat somewhere. Can anyone give me some clue's on what to check. I realize I need to provide some more configuration information but I thought I'd wait until someone lets me know exactly what to post. Thanks in advance


  • Richard
    06 Feb 2011

    There are several reasons why it might not work.

    Firewall blocking port 25, this can be detected by trying to acces the port using telnet from the machine itself.

    in you should have the line "inet_interfaces = localhost" removed, it restircts incoming connections to the local machine just like a firewall.

    Are you sure postfix is using port 25 and not some other process?

    This is a start, you can always chack your config against ours:

    Or read our tests here:

  • seventhfire
    06 Feb 2011

    Thanks for the quick response.
    I've shutdown the local system firewall. (or so the GUI indicates it is)

    I can access port 25 from the machine itself using telnet and get the Hostname ESMTP Postfix response.
    my inet_interfaces is commented out
    I'll investigate the information in the links you sent

    My goal is to get postfix configured to receive and send email alerts from systems on my local network. Not really interested in incoming mail at this point.

    Thanks again for the response

  • seventhfire
    06 Feb 2011

    I compared my with the one you gave me the link for and there seems to be a lot of extra stuff mysql, authentication etc.
    I'm running the default 2.5.5 nothing has been setup for authentication or database use.

    I did start with a new file, set the debug up, hostname, and verified inet_interface was commented out

    I opened another terminal while I was tailing the mail.log file and when my client connected I started getting the error below.
    postfix/master[4799]: fatal: bind port 25: Address already in use
    I've tried to shutdown postfix and use netstat to find out if there was another program using port 25 but postfix seems to keep restarting. (may have something to do with some old instructions I followed to get postfix up and running.
    As long as there isn't a client attaching I don't see the "Address already in use error.
    I do see a continuous restart of the postfix daemon. Is that normal?
    postfix/master[4845]: daemon started -- version 2.5.5, configuration /etc/postfix
    Feb 6 03:02:49 MightyMac postfix/master[4845]: master exit time has arrived
    Feb 6 03:02:49 MightyMac postfix/master[4873]: daemon started -- version 2.5.5, configuration /etc/postfix
    Feb 6 03:03:49 MightyMac postfix/master[4873]: master exit time has arrived
    postfix/master[4900]: daemon started -- version 2.5.5, configuration /etc/postfix
    postfix/master[4900]: master exit time has arrived
    postfix/master[4928]: daemon started -- version 2.5.5, configuration /etc/postfix
    postfix/master[4928]: master exit time has arrived
    postfix/master[4956]: daemon started -- version 2.5.5, configuration /etc/postfix
    postfix/master[4956]: master exit time has arrived

    Looks like I need to trouble shoot the looping restart. It may be the daemon is trying to restart when there is already one running.

    I may change the port its running on just to see if the error moves with the port change.

  • Richard
    06 Feb 2011

    Our setup is for a public facing mailserver. I'm not sure how one might fit within a local network as we rely on the public DNS infrastructure like MX records to determine mail delivery and routing.

    Maybe someone else can shed some light on this specific scenario.

  • seventhfire
    07 Feb 2011

    After fighting with this for a day I decided I would try another Mac system I have running Snow Leopard. After making the very simple changes to the default postfix settings, mynetwork, inet_interface I found the OS would allow connections to port 25 by all systems on my local network and would send email to the internet without problems.

    It would appear as though the 1st system I was working with has some under the hood network configuration issues which is preventing connections to port 25.

    In the past I had been experiencing problems with this system in with it not connecting to the network via DHCP so apparently what ever the problem is it is also affecting other port binding processes.

    So the bottom line is. The 2.5.5 default install of postfix to Snow Leopard works fine for accepting and relaying OUTGOING email from internal local network by just making a few basic adjustments in the

    Thanks for the help.

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