Create reverse DNS lookup on the PIX firewalls external IP address resolves to the MX servers name

Posted on 2005-04-20
Last Modified: 2008-03-06
I have an exchange server that sends mail out threw a Cisco PIX firewall.  The external ip address on the firewall is getting reject went sending mail to some clients.

DNS MX record is: using Redhat 7.0.

How do I create reverse DNS lookup foir the PIX firewalls external IP address so it resolves to the MX servers name?

Question by:Markloh
    LVL 104

    Expert Comment

    This is nothing to do with the firewall.

    The reverse DNS is set by your ISP - not your domain name registrar or whoever looks after your DNS. Reverse DNS is attached to the IP address, not your domain.
    You need to call the ISP and ask them to set the reverse DNS for you.


    Author Comment

    Thanks Simon,  I'll have to change that external ip on the PIX to a static address as the ISP can't reverse DNS for the current one.
    LVL 104

    Accepted Solution

    Your other option would be to use an SMTP Connector to send email via your ISP for domains that don't like your reverse DNS. This is what many of them want you to do anyway.


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