SMTP server

SMTP is the protocol used to transmit and receive Internet mail messgaes.
When you send a message from an Exchange client the SMTP server contacts either:
1. Another SMTP server to relay the email for you.
2. The destination SMTP host.
You can setup Exchange either way. However it is not necessary to do so. You can have Exchange Deliver the email on it's own. There is no need for you Exchange Server to contact your ISP's SMTP server first.
For receiving however there is other things involved.
If you want that all email arrive directly to your Exchange Server, then you will need:
1. A static IP Address (you can use a dynamic one but you this requires dynamic DNS as well, which might not be so reliable).
2. A MX record on a DNS server that points to your SMTP (Exchange) Server (MX stands for Mail eXchange, it tells for anyone that wants to know that the email server of your domain is located at whatever your IP Address is).
If however for whatever reason you don't want to use the above option (for receiving), you can do one of the following:
1. Have your ISP set up their Server that your server can pick up all mail using TURN/ETRN command. Those are 2 SMTP commands specificly designed for this purpose.
2. Use a POP connector on your Exchange Server that will pick up all your email from your ISPs server using POP and then distribute it into the Exchange boxes where it has to go. One such program (connector) is available from Microsoft (for free) for Small Buisness Server (not for the regular version). Another one is a program called popbeamer which you can obtain from www.popbeamer.com.
If you need any more help email me.