a new sendmail question

[Les Mikesell]

Tim wrote:
> On Mon, 2007-12-17 at 08:25 -0600, Aaron Konstam wrote:
>> I would claim that you do have a domain. The domain of the external
>> interface of your router. 
> 
> Hmm, claiming your ISP's domain as if it were your own can be a problem.
> All's fine and well if you simply use it with your e-mail addresses
> provided by your ISP.  But something like using root@ your ISP's domain
> name would be a major no-no.
> 
> You'd have to be very careful about keeping internal mail internal.
> That, pretty much, means you need to run your own DNS server, so that a
> mailserver doesn't to a MX lookup on the domain, using the ISP's name
> server, and send the message through the ISP's SMTP server.

There's another problem with most NAT routers.  Unless you provide your 
own internal DNS service so that the name resolves internally to the 
private address of the host you want to accept email, you will try to 
deliver it to the outside interface of the router.  Even if the router 
is configured to forward inbound connections from the external interface 
to the receiving host, most routers won't do this if the connection 
originates on the internal interface.

-- 
   Les Mikesell
    lesmikesell at gmail.com