Problem sending mail to 2nd SMTP server inside network

Discussion in 'Server Operation' started by kisong, Feb 28, 2006.

  1. kisong

    kisong New Member

    I've setup Postfix under Fedora Core 4 using ISPConfig and the "Perfect setup Guide" from this website.

    This box is connected directly to the Internet on IP address The mx server information is at

    On my internal network, there is a LISTSERV server. It has an internal IP address of It has an MX record of at (This IP address of is routed to the using NAT routing).

    When an e-mail goes to [email protected], it is routed perfectly. The listserv works flawlessly, both receiving and sending messages.

    However, when a message is sent to [email protected] from WITHIN our network, the following error message occurs:

    Feb 28 12:10:18 mail postfix/smtpd[2817]: connect from unknown[]
    Feb 28 12:10:18 mail postfix/smtpd[2817]: D2B963578A3: client=unknown[]
    Feb 28 12:10:18 mail postfix/cleanup[3446]: D2B963578A3: message-id=<C029EE25.1625C%[email protected]>
    Feb 28 12:10:18 mail postfix/qmgr[2578]: D2B963578A3: from=<[email protected]>, size=541, nrcpt=1 (queue active)
    Feb 28 12:10:18 mail postfix/smtp[3480]: connect to[]: Connection refused (port 25)
    Feb 28 12:10:18 mail postfix/smtp[3480]: D2B963578A3: to=<[email protected]>, relay=none, delay=0, status=deferred (connect to[]: Connection refused)
    Feb 28 12:10:18 mail postfix/smtpd[2817]: disconnect from unknown[]

    Is there a setting/conf file that I need to change so that the messages from WITHIN our network are routed properly and not refused by the LISTSERV?

    I'm pretty sure it has something to do with how Postfix sends the message to the LISTSERV, but I can't seem to find out how to do this properly.

  2. falko

    falko Super Moderator Howtoforge Staff

    Is it maybe a problem with your router not allowing loopbacks into your network?
    Or maybe a firewall setting?
  3. kisong

    kisong New Member

    I found the solution! It's a simple one, but I guess noone knew exactly what I was talking about.

    Basically, I needed to NIC cards: one to communicated directly within the network and a second one to connect directly to the internet. With this solution, I still maintain connectivity with the internal network (file sharing, etc.) and also avoid the problem of not being able to send internet mail from within the network.


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