[X4U] Email Server DNS issue?

[Philip J Robar]

On Dec 16, 2005, at 8:08 AM, Jesse Leo wrote:

> Hi all,
>
> 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.

You don't give enough information about how you network is set up,  
but one thing to be aware of is that if you're using NAT and mapping  
external ports of the public address to internal addresses some  
routers will not let you access the public address from within the  
internal network.

Issues like yours have been discussed extensively on the The OS X  
Server list (http://lists.apple.com/mailman/listinfo/macos-x-server).  
The general consensus is that you need to set up an internal DNS  
server to map names to private addresses for machines on the internal  
network. I have set this up on my home network and it works well.


Phil