Chapter V collaboration with HTTP Web server
A Web server can set up multiple independent Web site domain names can also be used as a transit server on the communication path to enhance the transmission efficiency.
1. To achieve multiple domain names with a single virtual machine
HTTP / 1.1 specification allows a HTTP server set up multiple Web sites. Even if the physical level, only one server, but as long as the use of virtual host, you can already have multiple virtual servers. In the same IP address, due to a number of different virtual host can register domain names and host Web sites, thus sending an HTTP request, you must specify the full URI host name or domain name in the header Host.
2. Communication data forwarding procedure: proxy, gateway, tunnel
In addition to the HTTP server and client, there are some applications for forwarding data communication, these programs may be forwarded to the next server requests the communication line, and receive a corresponding response.
[ Acting ] is a kind of proxy forwarding application, and it played a role in the server and the client "middleman" of receiving the request sent by the client and forwarded to the server, but also to receive a response returned by the server and forwarded to the clients.
The basic behavior of the proxy server is forwarded to another server after receiving a request sent by the client. The agent does not change request URI, it will be sent directly to the target server front to hold resources. Each time a request or response forwarded through a proxy server, additional writing Via header information.
Category: caching proxy, transparent proxy
[Caching proxy]: When forwarding proxy response, will advance copy of the resource stored on the proxy server.
[Transparent Proxy]: Acting is no treatment.
[Why Use a proxy server (advantage)] the use of caching technology reduces network bandwidth traffic , access control within the organization for a specific site in order to gain access to the log for the primary purpose.
[ Gateway when] the gateway server to other servers to forward communication data receiving requests from the client, and it's like they own resources as the source server to process the request. Sometimes the client may never notice that their goal is a communications gateway.
HTTP requests using the network can be converted into other communication protocols . Using the gateway can improve the security of communication , since the communication line between the client and the encryption gateway in order to ensure a secure connection. For example, the gateway can connect to the database, query data using SQL statements, in addition to credit card settlement on the Web shopping site, network management can be linked and credit card settlement system.
[ Tunnel ] tunnel is in transit between the two far apart the customer end and server, and keep both the application communication connection.
A tunnel may be required to establish a communication line with other servers, when the use of encryption, such as SSL communication. The purpose of the tunnel is to ensure that the client can communicate securely with the server. The tunnel itself will not go parsing (change) HTTP requests.
3. Save resources cache
Cache refers to a proxy server or resources to save a copy of the client's local disk. Players can reduce access the server by caching, saving time traffic and communication.
Cache server is a proxy server, caching proxy classified types. In other words, when the agent forwards the response back from the server, the proxy server will save a copy of the resource.
Cache not only exists in the cache server, you can also be present in the client browser , the client cache is called the Temporary Internet Files.