mail server DNS configuration questions

Paul Schmehl pschmehl_lists at
Sun Sep 7 04:59:15 UTC 2008

--On September 6, 2008 7:28:28 PM -0600 Andrew Falanga 
<af300wsm at> wrote:

> Hi,
> Well, my clients at church are still having issues and after working
> with  George, a respondant to my original questions, I think that most,
> if not all,  of my problems are related to DNS and how we've got it
> improperly configured.
> First, a crude drawing of how our mail server exists in the world:
> 192.168.2.x/24       "lot's of networks"
> Private Network <--> CableOne <--> Internet
> Now, our mail server's IP is  On the router, he (the
> person at  whose house the mail server is) has IP forwarding setup so
> that mail get's  sent to our FreeBSD machine.  Using dig, here's the
> responses:

The network is an IANA reserved network and **does not 
route** on the internet.  You can send mail but you'll never be able to 
receive any.  In order for you to receive email to that server, whatever 
device you've got in front of it (dsl router, for example) must be 
configured to "hard code" port 25 to your mail server so that all incoming 
mail to the public IP ( will always go to the 
address, which is the actual address of the mail server.

Some mail servers will not receive mail if the IP of the mail server 
doesn't reverse.  Yours does, so that shouldn't be a problem, *however* if 
they also try to talk to your mail server to verify that it's actually a 
mail server that will fail if you don't have port 25 "hard coded".

You don't say what the "issues" that you're having are, so that's my best 
guess about what's wrong.

Paul Schmehl, If it isn't already
obvious, my opinions are my own
and not those of my employer.
WARNING: Check the headers before replying

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