User access to the basic process of the site

1: Users visit www.baidu.com This site, the system will first look at the DNS cache or Hosts file information, determine if there is a domain name corresponding IP resolution record, if any, directly obtain an IP address. Generally, the first request, the DNS cache is not logged, and the Hosts file is generally used in internal testing.

2: If the client local hosts file or DNS cache does not have a corresponding resolution record, the system will send the resolution request to the Ldns (local DNS) server, if the LDNS server local cache has a corresponding resolution record will return the IP address directly to the client. If not, Ldns will be responsible for continuing the request to other DNS servers

3:ldns from the DNS system (.) The root begins to request parsing of the www.baidu.com domain name and a series of lookups for each level of the DNS service system. Finally, the baidu.com domain name corresponding to the authorized DNS server, and this authoritative DNS server is the Enterprise purchase domain name used to manage the domain name resolution of the server, this authorization server will have www.baidu.com corresponding IP resolution records. If not at this time, it indicates that the enterprise's Domain name manager did not set the resolution for www.baidu.com.

4:baidu.com authorized DNS servers send www.baidu.com final IP resolution records to LDNS

After the 5:LDNS server receives the IP address from the authorization server, it sends the IP to the client browser and caches the domain name and IP resolution so that the next time it is returned to the client more quickly, the cache records will not expire for a specified period (DNS TTL value control).

6: The client browser obtains the IP corresponding to the domain name, and after that, the browser will request to obtain the IP corresponding to the site server. The Web server receives the request and responds to processing. Returns the content requested by the customer to the customer's browser.

The Windows view local cache DNS Resolution logging command is as follows:

C:\> Ipconfig/displaydns

Clear the DNS resolution logging command for the Windows client local cache as follows:

C:\> Ipconfig/flushdns

The hosts domain name resolution records under Windows System are as follows:

C:\Windows\system32\drivers\etc\hosts

User access to the basic process of the site