Google Activation Guide Postini Email Security - Manual (Page 44)

50 Activation Guide
For detailed instructions on how to update your MX records, see “Change Your
MX Records” on page 15
Why should I update MX records?
For the message security service to work, we need you to route your mail to us.
When you update your MX records, we accept your mail, filter out the bad mail,
and pass the good mail on to your server.
When should I update my MX records?
During activation, you'll receive a message telling you it's time to update your MX
records.
If you're adding more domains later on, update your MX records after you've
added the domain in the Administration Console. Until your domain is set up in the
Administration Console, mail will bounce if you update your MX records.
What's the format of an MX record?
An MX record includes the following fields:
Name: The name of your domain.
Class: This is always set to IN, which stands for Internet.
Type: For MX records, this is always set to MX.
TTL: "Time to Live." How long it will take to update the record. This is measured in
seconds. A TTL of 3600 seconds means records will take an hour to update. A
TTL of 86400 means records will take a day to update. A higher TTL value means
less traffic load for the DNS server, but it also means that changing the MX
records will take longer.
Preference or Priority: The order of preference for mail delivery. Sending
servers should try the lowest preference number first, then the next lowest, and so
on.
Data: The host name of the mail server that handles mail for that domain.
For instance, if your domain is jumboinc.com, your MX records might look like
this:
jumboinc.com. IN MX 86400 1 jumboinc.com.s7a1.psmtp.com.
jumboinc.com. IN MX 86400 2 jumboinc.com.s7a2.psmtp.com.
jumboinc.com. IN MX 86400 3 jumboinc.com.s7b1.psmtp.com.
jumboinc.com. IN MX 86400 4 jumboinc.com.s7b2.psmtp.com.