[X4U] Email Server DNS issue?

[Nick Scalise]

> From: Jesse Leo <jleo at projectsupport.com>
> 
> Strange one here -- we have a email server on our LAN that is reachable 
from
> outside the LAN via a name: mailer.mydomain.com.
> 
> >From within the LAN, it can only be reached via the local LAN ip
> address, the name will not work.  Interestingly, a lookup of the name
> with Network Utility.app (from within the LAN) does correctly resolve
> to the outside ip address.
> 
> My initial thoughts were that it is a firewall issue, but I am not
> sure what settings would stop this from working.
> 
> We need this to work with the name from within the LAN so that those
> folks that use a powerbook as their workstation both at work and from
> home do not need to change email account settings.
> 
> Any ideas you guys have would be great.

Do you have internal and external DNS? 

It does sound like a firewall/NAT issue in that your external IP's are blocked 
from the internal network because the server has an internal IP of 10. or 
192.168. and also an external real IP.

I am no expert on this, I only have experienced something similar and this 
was our resolution.

--
Nick Scalise
nickscalise at cox.net