PLANNING

Examples of using multiple MX records
You can use a single Internet domain with a single domain name or single Internet domain name with two balanced servers when using multiple mail exchanger records (MX records).

Two examples for setting up multiple MX records in the DNS are as follows:


Using a single Internet domain with a single domain name

You can specify MX records for a single Internet domain -- for example, renovations.com -- with a single Internet domain name, such as renovations.com. Use the server's fully-qualified Internet host name in the MX and A records -- for example, mail1.renovations.com.

For example, configure a backup SMTP server (mail2.renovations.com) to deliver or forward mail when the primary SMTP server (mail1.renovations.com) is unavailable:

1. MX record: renovations.com IN MX 5 mail1.renovations.com


2. MX record: renovations.com IN MX 10 mail2.renovations.com
Using a single Internet domain name with two balanced servers

If you specify equal preference for two servers, DNS randomly selects a server to balance the load of incoming mail.

1. MX record: renovations.com IN MX 5 mail1.renovations.com


2. MX record: renovations.com IN MX 5 mail2.renovations.com
Using a single Internet domain with multiple domain names

You can create MX records for a single Internet domain -- for example, renovations.com -- with multiple Internet domain names -- for example, renovations.com, qrs.com, and xyz.com.

Note: Users can address mail to each domain name and each domain has a backup SMTP server.

1. MX record: renovations.com IN MX 5 mail1.renovations.com

2. MX record: renovations.com IN MX 10 mail2.renovations.com

3. MX record: qrs.com IN MX 5 mail1.renovations.com

4. MX record: qrs.com IN MX 10 mail2.renovations.com

5. MX record: xyz.com IN MX 5 mail1.renovations.com

6. MX record: xyz.com IN MX 10 mail2.renovations.com

Related concepts
Messaging overview