How to check the mx ptr record of a domain name

1) in the Windows system click "start" menu → "run" → "input cmd" (Windows 98 system is command), open the windows system MS-DOS interface. Enter the "NSlookup" command to go to the domain name resolution interface.

2) Enter "set q = mx" and press enter to enter the MX record query status.
Enter the main domain name of your company's email server, that is, the part after the "@" of the user's email address
For example: 163.com, china.com, etc.
This document uses china.com as an example to return the following rough information (the blue part is a comment ):

> China.com-this is the queried primary domain.
Server: ns-pd.online.sh.cn -- this is the currently used DNS host name
Address: 202.96.209.20.-- this is the current DNS host address

Non-Authoritative Answer:
China.com MX preference = 10, mail exchanger = mta.china.com
-- This is the host name pointed to by the MX record of china.com.

China.com nameserver = ns2.china.com
China.com nameserver = ns1.china.com
Mta.china.com Internet address = 211.99.189.179
-- This is the IP address of the Host Name pointed to by the MX record of china.com

Ns1.china.com Internet address = 61.151.243.136
Ns2.china.com Internet address = 202.84.1.101zz

3) The standard MX record should be resolved by the primary domain to a host name (mta.china.com in this example ), then, one or more IP addresses (211.99.189.179 and 211.99.189.180 in this example) are parsed from the host name, instead of an IP address directly resolved from the primary domain, the host name resolved by the primary domain name cannot be the same as the primary domain name.

4) Enter "set q = PTR" and press enter to enter the PTR record query status.

> 211.99.189.179-this is the IP address of the queried email server.
Server: ns-pd.online.sh.cn
Address: 202.96.209.20.

Non-Authoritative Answer:
179.189.99.211.in-ADDR. Arpa name = mta.china.com -- this is the host name pointed to by the PTR record of the IP address

189.99.211.in-ADDR. Arpa nameserver = ns.intercom.com.cn
189.99.211.in-ADDR. Arpa nameserver = ns1.intercom.com.cn
Ns.intercom.com.cn Internet address = 211.99.207.229
Ns1.intercom.com.cn Internet address = 211.152.53.3

5) Note: The Modification and addition of domain name resolution are only modified on the DNS of the domain name provider. the DNS server used by others may not be the same as the DNS server you applied for domain name resolution, therefore, after adding or modifying your domain name, you can see the correct resolution result only after synchronizing data between DNS servers. The synchronization in the same region may take several hours, and the National DNS synchronization may take two days. The Global DNS synchronization may take four or more days, so the domain name resolution cannot take effect immediately after the change.