Google Outbound Services Configuration Guide - Manual (Page 18)

Introduction to Outbound Configuration 19
Option 2: Set Up Smarthost
If you are using a mail server that does not currently support Private DNS, or if
you do not wish to use Private DNS, set up a smarthost on your server instead.
Once you’ve set up a reinjection host and added the IP range to the
Administration Console, redirect your mail to the email security service by setting
up a smarthost. Smarthost is a common term for a server that accepts outbound
mail and passes it on to the recipient.
Before you make changes, note your original settings, so that you can restore
your settings if any problems occur during setup.
The appropriate smarthost is
outbounds[your system number].obsmtp.com
where [your system number] is your system number. For instance, if you are
using System 6, your smarthost address is
outbounds6.obsmtp.com
To find your system number, see “Identify Your System” on page 13.
Setting up a smarthost is different for every server. For step-by-step instructions
for setting up a smarthost, see the appropriate chapter in this guide for your mail
server.
Test Outbound Mail
Once you have set up your smarthost (or private outbound DNS), test that your
configuration is correct and mail is flowing normally.
Testing outbound mail is different for every mail server type. For information on
testing outbound mail, see the documentation for your mail server.
Microsoft Exchange Servers
Setting up reinjection and smarthosts on different versions of Microsoft Exchange
Server can be especially complex. Different server types require different settings:
For Microsoft Exchange 5.5, see “Microsoft Exchange 5.5” on page 99.
For Microsoft Exchange 2003, the recommended method is Private Outbound
DNS. See “Microsoft Exchange 2003 (Private DNS Method)” on page 23.
For Microsoft Exchange 2007, the recommended method is Private Outbound
DNS. See “Microsoft Exchange 2007/2010 (Private DNS Method)” on page 31.
For Microsoft Exchange 2010, the recommended method is Private Outbound
DNS. See “Microsoft Exchange 2007/2010 (Private DNS Method)” on page 31.