About setting up MX records

Summary: Correctly set up mx (mail Exchanger) Mail exchange record is the basic condition of stable operation of enterprise e-mail Service, we often find that many enterprise e-mail administrators cause important external mail to be returned or lost due to the setting of non-conforming MX records.

Let's look at a common example:
yourdomain.com MX preference = ten, mail exchanger = 221.57.37.160

The MX record setting directly corresponds to the IP address, which is a non-RFC-compliant setting, according to the RFC's SMTP protocol setting standards, mail exchange Records MX should point to a record, rather than directly corresponding IP address.

The above example, the mailbox administrator should add an A record, such as
mail.yourdomain.com Internet address = 221.57.37.160

Then point the MX record to this a record:
yourdomain.com MX preference = ten, mail exchanger = mail.yourdomain.com

Check to see if your enterprise mail server's MX record is set up, but is this setting going to be a hassle-free thing?

The answer is in the negative.

Although the above yourdomain.com setting is RFC compliant, usually external mail can reach the server normally, but it is still not the recommended setting method because this setup lacks the redundancy of the network and mail server, and if the network transient is encountered or the mail server is temporarily unavailable, the external mail can still be returned or lost.

Let's look at a few examples:
1.IBM Company
ibm.com MX preference = ten, mail exchanger = e31.co.us.ibm.com
ibm.com MX preference = ten, mail exchanger = e32.co.us.ibm.com
ibm.com MX preference = ten, mail exchanger = e33.co.us.ibm.com
ibm.com MX preference = ten, mail exchanger = e34.co.us.ibm.com
ibm.com MX preference = ten, mail exchanger = e35.co.us.ibm.com
ibm.com MX preference = ten, mail exchanger = e1.ny.us.ibm.com
ibm.com MX preference = ten, mail exchanger = e2.ny.us.ibm.com
ibm.com MX preference = ten, mail exchanger = e3.ny.us.ibm.com
ibm.com MX preference = ten, mail exchanger = e4.ny.us.ibm.com
ibm.com MX preference = ten, mail exchanger = e5.ny.us.ibm.com
ibm.com MX preference = ten, mail exchanger = e6.ny.us.ibm.com

2.Yahoo Mailbox
yahoo.com MX preference = 1, mail exchanger = c.mx.mail.yahoo.com
yahoo.com MX preference = 1, mail exchanger = d.mx.mail.yahoo.com
yahoo.com MX preference = 1, mail exchanger = e.mx.mail.yahoo.com
yahoo.com MX preference = 1, mail exchanger = f.mx.mail.yahoo.com
yahoo.com MX preference = 1, mail exchanger = g.mx.mail.yahoo.com
yahoo.com MX preference = 1, mail exchanger = a.mx.mail.yahoo.com
yahoo.com MX preference = 1, mail exchanger = b.mx.mail.yahoo.com

3.126 Email
126.com MX preference = ten, mail exchanger = 126.mxmail.netease.com
126.com MX preference = $, mail exchanger = mxbak.126.com

4. Company email
corp-email.com MX preference = ten, mail exchanger = Mail.biz-email.net
corp-email.com MX preference = $, mail exchanger = Global-cdn.corpemail.net
corp-email.com MX preference = $, mail exchanger = mail.corpemail.us

The above domain name has a commonality, are set up multiple MX records, corresponding to multiple IP and mail server, mail server with network and server redundancy, so as to stabilize the acceptance of external mail.

We recommend that the Enterprise mail server need at least 2 MX records, considering the domestic north-south telecommunications interconnection problems, cross-telecommunications, Netcom dual IP best.
If your mail server uses telecom, Netcom dual IP access (or more than one mail server)
mail1.yourdomain.com Internet address = Telco IP addresses
mail2.yourdomain.com Internet address = netcom IP addresses
yourdomain.com MX preference = ten, mail exchanger = mail1.yourdomain.com
yourdomain.com MX preference = ten, mail exchanger = mail2.yourdomain.com

Sometimes, the company's overseas mail is particularly important, we can consider adding an overseas mail server as an alternate entrance to the mail, if the mail server encountered overseas customers can not connect to the domestic network, then mail through the overseas mail server after the transfer to the Enterprise mail server.
Please refer to the setup of the 4th example above.
corp-email.com MX preference = $, mail exchanger = mail.corpemail.us

If you use IDC's products each IDC website generally has its own tutorials, it is not possible to contact IDC online customer service!

About setting up MX records