Actually, the split DNS would be the best solution for me. Changing the DNS
per server is easy compared to changing the routes in the entire network. 

I found a product that would auto create a private MX only record when I
create a private record for a domain. 

This is the only solution that I found that is so far feasible. 

The reflection as I found out through extensive testing isn't working at
all. I don't know if it's a bug in the latest version or so, but I spent up
all last night testing, retesting, and testing again over and over and it
isn't working. PF is responding just as m0n0wall does, reflection on or not.


Either way, I will wait until the next version of PF before attempting it
again but split DNS is the best option.

Thanks everybody for your imput. INTENSELY helpful and appreciated. 





-----Original Message-----
From: Dimitri Rodis [mailto:[EMAIL PROTECTED] 
Sent: Thursday, February 07, 2008 12:14 PM
To: [email protected]
Subject: RE: [pfSense Support] Multiple servers behind NAT'd firewall

Angelo,

pfSense specifically has a feature known as NAT reflection which allows
this to be possible, mainly because split horizon DNS is not always a
reasonable solution. In the case of the person who started this thread,
he has approx 700 email domains across various servers behind a NAT-- so
when someone from one domain on one server tries to email another person
within the same "system" (but on different servers), SMTP won't connect
because the MX record resolves to a public IP (as it should). I have the
exact same issue myself, with the exception that the number of domains I
have to deal with is probably 30-40 somewhere. 

So in these cases, what would you choose? ;)

Dimitri Rodis
Integrita Systems LLC 

-----Original Message-----
From: Angelo Turetta [mailto:[EMAIL PROTECTED] 
Sent: Thursday, February 07, 2008 1:09 AM
To: [email protected]
Subject: Re: [pfSense Support] Multiple servers behind NAT'd firewall

Trave Harmon wrote:
> Mine is on but it still doesn't work. 
> 
> Is there a way to verifiy at the command prompt level if it is
working?
> 
> -----Original Message-----
> From: Dimitri Rodis [mailto:[EMAIL PROTECTED] 
> Sent: Wednesday, February 06, 2008 8:10 PM
> 
> Maybe I'm off the mark by saying this, but I think NAT reflection
should
> be ON by default-- can't think of any security risks associated with
it
> really, since the machine you are trying to hit is presumably already
> behind the same NAT as you are..
> 
> That would solve any future issues, anyway..

Wait a minute, historically the BSD stack (or at least the FreeBSD 
implementation) has always been unable to do NAT on a single interface.

To be more clear, it's not possible to rewrite a packet and have it 
leave the stack back on the same interface from which it came on first
hand.

Please read http://www.openbsd.org/faq/pf/rdr.html#reflect (see: 
Redirection and Reflection )

So, reflection rules work great if the LAN hosts need to access the 
NAT-ed hosts on a DMZ, but not on single internal lan (or, in my 
example, for reciprocal access by the DMZ hosts).

In your case the solution is 'Split-Horizon DNS'. Put the addresses of 
all the MX servers in a single dns zone, and configure the servers 
themselves to receive resolution for that zone from an internal DNS 
which will hand out internal IPs.

Angelo Turetta

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