RE: problems receiving e-mail to my server redux

From: Cowles, Steve (steve_at_stevecowles.com)
Date: 07/09/04

  • Next message: Robert Canary: "Re: getting the GUI at login" 
    To: "'General Red Hat Linux discussion list'" <redhat-list@redhat.com>
Date: Thu, 8 Jul 2004 17:24:19 -0500

    Ed McCorduck wrote:
    >
    > Thanks for your very detailed reply, Steve. I'll try to dig through
    > your mine of information as best as I am able, but unfortunately it's
    > mostly way over my head at the present state of my newbie knowledge.

    Ed,

    In short...

    1) Your domain regsitration seems to be correct. i.e. The recursion from the
    root servers back to your name server is working.

    2) Whats not working are queries to your name server; which is listed at
    24.24.15.155. Is this the public IP address for your firewall?

    3) The reply I got back from the above IP address was an ICMP port
    unreachable. This is usually caused by your firewall not being properly
    configured for NAT'ing (port forwarding) to an internal RFC1918 address. In
    your case, 192.168.1.101

    > At least I understand one of your questions, though, and perhaps my
    > answer can shed more light on the problem:
    >
    >> BTW: Is 192.168.1.101 possibly a host behind your firewall???
    >
    > Yes, 192.168.1.101 is the IP address that I maintain for my Linux
    > computer, which houses my Web and e-mail (sendmail) servers. My
    > firewall, which is an integral part of my Linksys router for my home
    > network, I set up through Port Forwarding to send all port 25, 80 and
    > 110 queries to this computer.

    As I suspected. Please note that DNS queries require udp and tcp port 53 to
    be port forwarded. You don't mention these ports above. Also, if your mail
    server is also at 24.24.15.155, then connections to it are not working. i.e.

    telnet 24.24.15.155 25
    Connecting To 24.24.15.155...Could not open connection to the host, on port
    25:
    Connect failed

    Are you sure your ISP is not blocking inbound smtp connections? A lot of
    ISP's are blocking smtp connections for residential customers. If so, then
    fixing your DNS problem is pointless.

    Steve Cowles 

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