Original: http://106.13.73.98/__/191/
Most network communication is based on TCP / IP protocols, and TCP / IP is based on IP address, it can only identify as "202.96.134.133" Such an IP address to communicate on the computer network, but does not recognize the domain name. We can not remember a lot of sites like this one IP address, so when we visited the site, it is more desirable enter the domain name in the browser address bar, you can see the pages you need. Thus, DNS服务器it was born, we can name it "translated" into the corresponding IP address.
The so-called DNS server
The DNS (Domain the Name System) is the Domain Name System abbreviation, which is used TCP / IP network, the services it provides are used to convert the host name or domain name to an IP address. The basic operating principle as shown below:
Full DNS resolution process
When the user inputs the address bar, such as: when www.baidu.com, DNS parsing roughly the following procedure:
- First, check your browser's own cache, there is no corresponding IP address This domain name (whether before parsed), and if so, rendering is completed.
- If the browser does not cache (called a professional point miss), the browser will check the operating system cache have been resolved without a corresponding domain name.
Process control system also has a name resolution, through the windows of the hosts defined in the file, if you were here a domain name corresponding to the IP address specified, then the browser will be the first to use this IP address.
- If the domain name so far has not been hit, it will really request the local domain name server - LDNS , to resolve the domain name. This server is generally somewhere in your city, not very far away from you, and the performance of these servers are good, generally cached DNS result, about 80% of the domain name resolves to complete here.
- If LDNS not yet hit the jump directly to the Root Server (root name server) request resolution. Root name server returns to LDNS a queried domain gTLD Server (primary domain name server) address, which is the top international domain name server, such as: .com .cn .org and so on. At this point, LDNS again gTLD Server Send request.
- Accept the request of the gTLD Server query and returns the corresponding domain name Name Server address is the site registered domain name server.
- LDNS again Name Server initiated request, Name Server to find the target IP according to the mapping table, and returned to LDNS .
- At this time, the LDNS the analysis results returned to the user, while the cache address of the corresponding IP.
Reprint:
https://www.cnblogs.com/gopark/p/8430916.html
https://blog.csdn.net/m0_37812513/article/details/78775629
Original: http://106.13.73.98/__/191/