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Exchange 2003 can't receive external emails

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  • Exchange 2003 can't receive external emails

    Hello All,

    I got a block of 5 public static IP addresses from Uverse and want to experience with EX2k3.
    I did install Exchange 2k3 on a win 2k3 std server and it is working behind a NAT firewall. I've changed the host A and MX records to point to my adress.

    ex2k3 (

    A host A record =
    A MX record = points back to the host A record from ISP.

    Internal mail routing (in local domain) = no problem
    Here is the fun part:
    - At first, I was not able to send out emails to external domains, but I can receive it from external domains (gmail, yahoo, ..etc).
    I have SMTP virtual and the connectors setup in ex2k3.
    I called AT&T and asked them them to unblock outgoing smtp port 25.

    - After AT&T unblock outbound port 25, I have a reverse problem. When sending mails to other domains (internet outgoing mail), it is working fine with no problem. However, I can't receive internet emails now from external domains. I have recipient policy setup, mail server is reachable from the internet, MX and A records are there in place which point to the public static IP addresses i have from the ISP, virtual SMTP and connector are there too.

    What else could it wrong that I can't seem to trace out?
    Please help if you have any clue why it is not working.
    Thanks for your feedback.

  • #2
    Re: Exchange 2003 can't receive external emails

    have you tested a connection from the external network, to port 25 on the external IP of the firewall ?
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