Choosing the domain name

Hello all,

I'm trying to set up an server for my company. We have a
domain for our e-mail (pop3) and website which is lca-
services.nl .

We want to send and receive e-mail with our new server
using Batched SMTP and we want to host our own website
using IIS. And all of that from behind ISA Server.

My question is; how do I have to set up the domain name?
Should I make it lca-services.nl or should I make it lca-
services.local ? Someone told me that if I make it lca-
services.nl I can expect problems while sending mail
because the server won't know the difference between the
external and internal domain. Is this true or is it just
the opposite?

Any help would be greatly appriciated!

René Kas
The Netherlands