You have an Exchange Server 5.5 for your intranet email needs and you want to connect it to the internet so that your staff can receive email from all over the world.
Before your Exchange Server can receive mail from people all over the world, you have to SPEND alot to:
run your own SMTP/HTTP/NNTP service
get a class C IP address for your Exchange Server
run your own DNS or have your ISP add an MX record
get an expensive leased line with router and/or CSU/DSU or ISDN line
have your ISP (sigh...) support ESMTP with ETRN or TURN or finger or rsh...
The pocket hurts, doesn't it? Better turn back for Plan B.
