Services that need mail server - Use an outside mail server

Question

Hello,
I have a mail server somewhere on the internet, and outside my localnetwork.
Our OSX local server serves few services : DNS (for local dns name) OD, Ical, Ichat, Afp, Mobile access, vpn
Do they services use mail server locally ?
Do I need to setup a mail server localy or can I use my outside mail server ?
If needed
If I just set on every OD users, a mail as [email protected] and if my internet mail servers has an account for them, how can I define for these users the smtp/pop accounts to allow them to send mail through my net mail server ?
Do I have to setup a local mail server and accept in my internet mmail server this local mail server to relay mail in ?
In fact, what I'd like is to keep this internet mail servers, and set all my OD users using this mail server.
Thanks for your help, and sorry for my poor English. Hope you undurstood

Answer 1

I don't think you need mail services running to use any of those services. I can't speak for mobile access because I don't use that service. I think iCal and iChat need an email address for each user. You can set that in the info tab for each user in workgroup manager.