Google Outbound Services Configuration Guide - Manual (Page 51)

Microsoft Exchange 2000/2003 Multi-Server (Smarthost method) 55
Microsoft Exchange 2000/2003 Multi-
Server (Smarthost method)
Chapter 5
About Microsoft Exchange 2000/2003 Multi-Server
Microsoft® Exchange Server 2000/2003 is designed as a high-end, scalable
system. Microsoft Exchange 2000/2003 servers can be set up to work together in
a large email network. It is possible to route all outbound mail through the Email
Security Server without affecting the flow of internal mail between servers.
This chapter describes how to set up Outbound Services for an environment with
a multi-server Microsoft® Exchange Server 2000/2003 environment using a
smarthost.
The recommended method for setting up Outbound Servers with Microsoft
Exchange 2003 is Private Outbound DNS. For more information, see “Microsoft
Exchange 2003 (Private DNS Method)” on page 23.
An important concept in Exchange 2000/2003 multi-server environments is the
bridgehead server. A bridgehead server is a mail server that connects to the
Internet. Other servers will route outgoing mail to the bridgehead server, which
forwards mail to the Internet. Most of this configuration in this chapter applies only
to the bridgehead server.
More complex environments with non-standard routing group/bridgehead
configurations may require the use of a separate outbound gateway server:
• The routing group bridgeheads must relay all outbound mail to the gateway
server.
• The gateway server must forward all mail to the email security service as a
smarthost.
The gateway server can be any platform: another MS Exchange server, an MS IIS
server, or any other standard MTA software such as Sendmail, Postfix, etc.