What is a host header

1, the so-called main head of the name from IIS in the domain binding function, the general Web server an IP address of the 80 port can only correctly correspond to a Web site, processing a domain name access request. The Web server, without using multiple IP addresses and ports, requires a mechanism to distinguish the requests of different Web sites on the same IP address if it is necessary to support multiple, relatively independent sites, which presents a method of host header binding. Simply put, the different site space corresponding to different domain names, to connect the domain name field in the request to distribute and answer the correct corresponding space of the file execution results. For example, a server IP address of 192.168.1.10, with two domain names and corresponding space on this server, uses the 192.168.1.10 80 ports to provide services. If the domain name records of two domains A and B are simply resolved to this IP address, then the Web server will be receiving any request feedback is the same site information, which is clearly not up to the requirements. Next we use host headers to bind domain A and b to their corresponding space folders C and D. When the Web request information containing a domain A is reached 192.168.1.10, the Web server executes the first file of its corresponding space C and returns it to the client, which contains the Web request information of Domain B, which is interpreted only as a document of space d. Therefore, the use of Host header binding function can not use IP address to access any site on it, because the request information does not exist domain name information, so there will be an error.