We often come into contact with the domain name, and have been using, you need to know the domain name registration fee, then the price in the end who is given
A, ICANN
Worldwide domain name supreme governing body, called ICANN (Internet Corporation for Assigned Names and Numbers) organization based in California.
It turned out to be the United States Department of Commerce following a non-profit organization, so it was said, the US government control of the domain name around the world, this argument is well founded, in 2016, the US government announced, ICANN is no longer affiliated with the Ministry of Commerce, has become a self-governing independent body, but can be imagined, the US government still has an absolute effect on him.
ICANN loser worldwide domain name system management and operation. It's a major undertaking, it is to require top-level domain (top level domain, abbreviated as TLD).
Two, TLD
What is the top domain name, simply put, it is the last part of the URL. .Com top-level domain is such as www.example.com
ICANN's loser provision, which strings can be used as top-level domain, so far a total of more than 1,000 top-level domain.
Can be divided into two categories, one is a generic top-level domain (gTLD), such .comas, .net, .edu, .org, , .xxx 等等，共有700多个，另一类是国别顶级域名（CCTLD），代表不同国家和地区，such as .cn(China), .io(British Indian Ocean .ccTerritory), (Cocos Islands), .tv(Tuvalu), a total of 300 more.
Third, the top-level domain hosting providers
ICANN will not go to manage these top-level domains, because there are more than 1,000 top-level domain, each top-level domain names below are a number of wholesalers, if each must be managed, it is very troublesome.
ICANN's policy is that each top-level domain are looking for a hosting provider, to manage all the things in this domain. Such as .cn domain hosting business is the China Internet Network Information (CNNIC), he determines the various policies .cn domain names, and prices.
Currently, the world's largest top-level domain hosting providers is the US company Verisign.
Four, Verisign
Verisign is a commercial company, headquartered in Virginia, USA. It hosted the .com, .net , .name, .govfour generic top-level domain names, as well as .ccand .tvtwo national top-level domain. In addition, .eduand .jobsback office work, but also outsourced to it.
It .comand .netthe exclusive monopoly formed by history. The first time, Network Solutions company commissioned the National Science Foundation, managing top-level domain. In 2000, Verisign bought the company, inherited the domain name business. In 2003, Verisign sold the domain name registration business, leaving only the top-level domain management. In other words, it only domain wholesale, not retail the domain name.
In 2010, Verisign again website security and encryption certificate business was sold to Symantec Corporation. Which in turn in 2017 he sold the business to DigiCert.
Five, ICANN and Verisign lawsuit
It stands to reason, Verisign ICANN is the largest custodian, the relationship between the two should be a good son. The fact is that they have a poor relationship, and even fought the lawsuit.
The reason is that, ICANN is a non-profit organization supported by the government, non-profit goal, and Verisign is a commercial company, the pursuit of profit maximization, must pay an annual fee for hosting a large number of the former. Two of contradiction stems from this.
In 2003, Verisign has launched a new service Site Finder, user access is not registered with .comor .netdomain name, will be directed to Verisign's website. This means that it does not in fact have all the registered .comand .netthe domain name. Within a few days, Verisign to squeeze into the top 10 sites around the world.
ICANN requires Verisign immediately stop the business, otherwise it will terminate domain hosting contract. Verisign succumbed to stop this business, but then put ICANN to court, asking the court to please PCT contract between the two, ICANN in the end there is no right to interfere in its business.
The end of 2006, they reached a court settlement. ICANN agreed to extend Verisign top-level domain hosting contract, and agreed to limit a single domain name registration fees charged to consumers Verisign, from $ 6 to $ 7.85. The cost of the standard, has been in use to this day, you go to a registration .comor .netdomain, the money to pay the management fee of $ 0.18 is charged by ICANN, Verisign custodian fee of $ 7.85 is charged for the rest of the money is the cost of domain name retailers.
If a .comor .netdomain name costs $ 10, ICANN and Verisign total take of $ 8.03.
Later, Verisign top-level domain hosting contract was extended twice, the current contract to expire until 2024.
On the surface, ICANN let Verisign got huge monopoly profits. (The company had proposed to host it as long as the .comdomain name, the domain of a single custodian fees can be reduced to $ 1 per year.) But in fact, ICANN another way to play the market forces that it continues to improve top-level domain the number and variety. If you feel that .comthe domain name is too expensive, you can apply for other top-level domains, there are more than 1,000 top-level domains as you want.
Sixth, the root domain name
Because ICANN manages all of the top-level domain, so it is the highest-level domain node, called the root domain (root domain). In some cases, www.example.combeen written www.example.com., that will be the last one more point. This point is the root domain.
In theory, all DNS queries must first check the root domain, because only root domain name will tell you that a top-level domain is managed by which server. Fact true, ICANN maintains a list (corresponding hosting server's address), which records it and the corresponding top-level domain hosting providers.
For example, I want to visit www.example.com, you must first ask ICANN's domain name with the list, it will tell me the .com domain is hosted by Verisign, I have to go to Verisign, and it will tell me where example.com server .
As another example, I would like to visit abc.xyz, must go ask the root name list, it will tell me .xyzthe domain name is hosted by CentralNic company. Root domain name list also records, .googlehosted by Google, Inc., .applehosted by Apple and so on.
Because the root list of domain names rarely change, most DNS service provider will offer its cache, it queries the root domain name in fact is not so frequent.
Seven, DNS root zone
The official name is the root domain name list of DNS root zone (DNS root zone), ICANN's official website you can see the root zone file .
Save the file hosting information for all top-level domain, it is very large, more than 2MB.
For example, the top-level domain .comcan be found 13 domain name server.
com. 172800 IN NS a.gtld-servers.net. com. 172800 IN NS b.gtld-servers.net. com. 172800 IN NS c.gtld-servers.net. com. 172800 IN NS d.gtld-servers.net. com. 172800 IN NS e.gtld-servers.net. com. 172800 IN NS f.gtld-servers.net. com. 172800 IN NS g.gtld-servers.net. com. 172800 IN NS h.gtld-servers.net. com. 172800 IN NS i.gtld-servers.net. com. 172800 IN NS j.gtld-servers.net. com. 172800 IN NS k.gtld-servers.net. com. 172800 IN NS l.gtld-servers.net. com. 172800 IN NS m.gtld-servers.net.
In other words, .comthe analysis results of the domain name, this can go to 13 servers either a query. Careful readers may find that these are also using a domain name server itself (for example a.gtld-servers.net.) to identify, then had to go to query the server to which they point, it is easy to cause cyclic query.
Therefore, DNS root zone will also provide IP addresses (IPv4 and IPv6) of these servers.
a.gtld-servers.net. 172800 IN A 192.5.6.30 a.gtld-servers.net. 172800 IN AAAA 2001:503:a83e:0:0:0:2:30 b.gtld-servers.net. 172800 IN A 192.33.14.30 b.gtld-servers.net. 172800 IN AAAA 2001:503:231d:0:0:0:2:30 c.gtld-servers.net. 172800 IN A 192.26.92.30 c.gtld-servers.net. 172800 IN AAAA 2001:503:83eb:0:0:0:0:30 ... ...
Eight, the root name servers
Save DNS root zone file server, called DNS root name server (root name server).
Since the early DNS query result is a 512-byte UDP packet. This package can accommodate up to 13 address of the server, and therefore the provisions around the world 13 root name servers, numbered a.root-servers.netup to m.root-servers.net.
This 13 root name servers operate independently by the 12 organizations. Which, Verisign company management both root name server: A and J. Each company in order to ensure the availability of root name servers, deploy multiple nodes, such as Verisign, a company solely on the deployment of the 104 sets of root name servers (January 2016 data).
Therefore, the root name servers in fact more than 13 units . According to statistics, as of January 2016, the world total of 517 sets of root name servers. You can find information about all the root name servers in http://root-servers.org this site.
Although the root name servers have a domain name, but at least one must know the IP address, otherwise it will fall into the cycle of inquiry. In general, the machines are stored cache the IP address of a root name server, called name.cache file.
A.ROOT-SERVERS.NET. 3600000 A 198.41.0.4 A.ROOT-SERVERS.NET. 3600000 AAAA 2001:503:ba3e :: 2:30 B.ROOT-SERVERS.NET. 3600000 A 199.9.14.201 B.ROOT-SERVERS.NET. 3600000 AAAA 2001:500:200 :: b C.ROOT-SERVERS.NET. 3600000 A 192.33.4.12 C.ROOT-SERVERS.NET. 3600000 AAAA 2001:500:2 :: c ... ...
This file records the IP address of the 13 sets of domain name root server.