What Is an Address of Record?

A PTR record is a type of mail exchange record in an email system; another mail exchange record is an A record (in the IPv4 protocol) or an AAAA record (in the IPv6 protocol). PTR records are often used for reverse address resolution.

PTR record

Right!

PTR record, yes

PTR (Pointer Record), pointer record, yes

PTR records are used

To check domain name MX PTR (reverse resolution) records:

1) Click "Start" menu "Run" "Enter cmd" in Windows system (command for Windows98 system) to open the MS-DOS interface of windows system. Enter the "nslookup" command to enter the domain name resolution interface.

2) Enter "set q = mx" and enter the MX record query status. Enter the primary domain name of your company's mail server, which is the part after the "@" of the user's email address, such as: 163.com, China.com, etc. China.com as an example returns the following general information (the blue part is a note):

> china.com This is the main domain server: ns-pd.online.sh.cn --- This is the DNS host name currently used Address: 202.96.209.133 --- This is the DNS host address currently used

Non-authoritative answer:

china.com MX preference = 10, mail exchanger = mta1.china.com

china.com MX preference = 10, mail exchanger = mta2.china.com

china.com MX preference = 10, mail exchanger = mta3.china.com

This is the 3 mail host names pointed to by MX records of china.com

mta1.china.com internet address = 211.99.189.179

mta2.china.com internet address = 211.99.189.180

mta3.china.com internet address = 211.99.189.184

-This is the IP address corresponding to the 3 mail host names pointed to by the MX record of china.com

china.com nameserver = ns2.china.com

china.com nameserver = ns1.china.com

-These two are responsible for resolving the DNS server hostname of china.com

ns1.china.com internet address = 61.151.243.136

ns2.china.com internet address = 202.84.1.101

-These two are responsible for resolving the IP address corresponding to the DNS server hostname of china.com

Sometimes, only the host name corresponding to MX is displayed in the result of querying the MX record, but the IP address corresponding to the host name is not displayed (such as the MX analysis result of Shanghai Telecom DNS).

> set q = a --- Enter A record resolution mode and enter the host name to resolve the IP address:

> mta1.china.com-enter the mail server host name for query

> Non-authoritative answer:

Name: mta1.china.com

Address: 211.99.189.179

--- Get IP address

3) The standard MX record should resolve a host name (mta.china.com in this example) from the main domain, and then resolve one or more IP addresses from this host name (211.99.189.179 and 211.99 in this example) .189.180), and an IP address cannot be resolved directly from the primary domain, and the host name resolved by the primary domain should not be the same as the primary domain name.

4) Enter "set q = ptr" and enter the PTR record query status

> set q = ptr> 211.99.189.179-Enter the IP address of the mail server you are querying

Server: ns-pd.online.sh.cn-This is the DNS server host name currently used for resolution

Address: 202.96.209.133-This is the DNS server address used for resolution

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 this 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 individual DNS of the domain name provider. The DNS server used by others may not be the same as the DNS server that you applied for domain name resolution, so when your domain name is added or modified, you have to wait. Only after the data is synchronized between the DNS servers can you see the correct resolution result. Synchronization in the same area may take several hours, national DNS synchronization may take 2 days, and global DNS synchronization may take 4 days or more, so domain name resolution changes cannot take effect immediately worldwide.