About kaixinnet Server

1. kaixin.com's main site uses the DNS round-robin technology. The so-called DNS round-robin means that a domain name corresponds to several a records. For example, kaixin.com's main site has 6 servers.
DNS round-robin has a disadvantage. If a domain name points to a server or several servers (for example, a Web server stops providing services), DNS round-robin cannot be judged.
C:/users/caihuafeng> NSLookup www.kaixin001.com
Server: ns.crcbj.com
Address: 61.233.9.9

Non-authoritative response:
Name: a.kaixin001.com
Addresses: 220.181.100.30
220.181.100.35
220.181.100.33
220.181.100.34
220.181.100.32
220.181.100.31
Aliases: www.kaixin001.com

2.a.kaixin001.com should be the alias of the domain name www.kaixin001.com, that is, you can use http://a.kaixin001.com/in the same way.
C:/users/caihuafeng> NSLookup a.kaixin001.com
Server: ns.crcbj.com
Address: 61.233.9.9

Non-authoritative response:
Name: a.kaixin001.com
Addresses: 220.181.100.31
220.181.100.35
220.181.100.32
220.181.100.34
220.181.100.33
220.181.100.30

3. query the DNS ns.crcbj.com
C:/users/caihuafeng> NSLookup-Qt = NS ns.crcbj.com
Server: ns.crcbj.com
Address: 61.233.9.9

Crcbj.com
Primary name server = dns7.hichina.com
Responsible mail ADDR = hostmaster.hichina.com
Serial = 2008070200
Refresh = 3600 (1 hour)
Retry = 600 (10 mins)
Expire = 604800 (7 days)
Default TTL = 3600 (1 hour)

4. view the mail server status of kaixin.com
According to the NSLookup query results, I guess mail1.kaixin001.com and mail2.kaixin002.com should be kaixin.com's email server. kaixin.com has tens of millions of users, and it is normal to have two dedicated email servers ~ Ns4.kaixin001.com the four servers should be kaixin.com domain name servers
C:/users/caihuafeng> NSLookup-Qt = mx kaixin001.com
Server: ns.crcbj.com
Address: 61.233.9.9

Non-authoritative response:
Kaixin001.com MX preference = 10, mail exchanger = mail1.kaixin001.com
Kaixin001.com MX preference = 20, mail exchanger = mail2.kaixin001.com

Kaixin001.com nameserver = ns3.kaixin001.com
Kaixin001.com nameserver = ns1.kaixin001.com
Kaixin001.com nameserver = ns2.kaixin001.com
Kaixin001.com nameserver = ns4.kaixin001.com
Mail2.kaixin001.com Internet address = 123.125.59.127
Mail1.kaixin001.com Internet address = 119.161.132.228
Ns2.kaixin001.com Internet address = 220.181.100.173
Ns1.kaixin001.com Internet address = 123.103.102.240
Ns3.kaixin001.com Internet address = 119.161.132.240
Ns4.kaixin001.com Internet address = 123.125.57.13

5. Simulation of kaixin.com domain name resolution process

By default, NSLookup uses the DNS server in the local TCP/IP configuration for query, but sometimes we need to specify a specific server for query test. At this time, we do not need to change the TCP/IP configuration of the local machine. Just add the specified server IP address or domain name to the end of the command. This parameter is necessary for troubleshooting a specified server. In addition, we can directly query the results of the authorized server by specifying the server to avoid the results cached by other servers.

For example, the following test under the Domain Name Server f.gtld-servers.net can not find the domain name www.kaixin001.com resolution results, and in the Domain Name Server ns1.kaixin001.com can query the domain name www.kaixin001.com resolution results, indicating that the Domain Name Server region to maintain the domain name www.
C:/users/caihuafeng> NSLookup-norecurse www.kaixin001.com f.gtld-servers.net
(Root) nameservers = c.root-servers.net
(Root) nameservers = h.root-servers.net
(Root) nameservers = B .root-servers.net
(Root) nameservers = f.root-servers.net
(Root) nameservers = d.root-servers.net
(Root) nameservers = a.root-servers.net
(Root) nameservers = j.root-servers.net
(Root) nameservers = l.root-servers.net
(Root) nameservers = g.root-servers.net
(Root) nameservers = e.root-servers.net
(Root) nameservers = k.root-servers.net
(Root) nameservers = I .root-servers.net
(Root) nameservers = m.root-servers.net
C.root-servers.net Internet address = 192.33.4.12
H.root-servers.net Internet address = 128.63.2.53
H.root-servers.net AAAA IPv6 address = 2001: 500: 1: 803f: 235
B .root-servers.net Internet address = 192.228.79.201
F.root-servers.net Internet address = 192.5.5.241
F.root-servers.net AAAA IPv6 address = 2001: 500: 2f: F
D.root-servers.net Internet address = 128.8.10.90
A.root-servers.net Internet address = 198.41.0.4
A.root-servers.net AAAA IPv6 address = 2001: 503: ba3e: 2: 30
J.root-servers.net Internet address = 192.58.128.30
J.root-servers.net AAAA IPv6 address = 2001: 503: c27: 2: 30
L.root-servers.net Internet address = 199.7.83.42
G.root-servers.net Internet address = 192.112.36.4
Server: Unknown
Address: 192.35.51.30

* ** Unknown cannot find www.kaixin001.com: Bad error value

C:/users/caihuafeng> NSLookup-norecurse www.kaixin001.com ns1.kaixin001.com
DNS request timed out.
Timeout was 2 seconds.
Server: Unknown
Address: 123.103.102.240

Name: a.kaixin001.com
Addresses: 220.181.100.31
220.181.100.30
220.181.100.34
220.181.100.32
220.181.100.33
220.181.100.35
Aliases: www.kaixin001.com

Similarly, input NSLookup-norecurse into memory, NSLookup-norecurse www.kaixin001.com logs, NSLookup-norecurse www.kaixin001.com logs will have similar resolution results, but the IP address output sequence behind addresses is not the same.