HTTP Knowledge Popularization series: Web server with HTTP collaboration

1. The http/1.1 specification allows a single HTTP server to build multiple Web sites.
2. Under the same IP address, the URL of the host or domain name must be fully specified in the host header when sending an HTTP request because the virtual host can store multiple Web sites with different hostname and domain names.
3. HTTP communication, in addition to clients and servers, there are applications for communication data forwarding, such as proxies, gateways, and tunnels.
   1. An agent is a forwarding feature that acts as a "middleman" in the service side and the client.
   2. A gateway is a server that forwards communication data from other servers.
   3. A tunnel is an application that relays between a client and a server that is far apart and maintains a communication connection between the two sides.
4. Reasons to use a proxy server:
   1. Reduce network bandwidth traffic with cache technology
   2. Intra-organization access control for specific websites
   3. For the primary purpose of obtaining access logs
5. Two baseline classifications for proxy usage: whether to use the cache, or whether to modify the message.
6. Cache proxy: When a proxy forwards a response, the cache proxy pre-saves a copy of the resource on the proxy server.
7. Transparent proxy: Do not do any processing of the message agent.
8. The gateway enables the server on the communication line to provide non-HTTP protocol services. Gateways can improve the security of communications because they can be encrypted on the communication lines between the client and the gateway to ensure the security of the connection.
9. The tunnel can be as required to establish a communication line with other servers, using SSL and other encryption means to communicate. The purpose of the tunnel is to ensure that the client can communicate securely with the server.
10. A cache is a copy of a resource that is saved within a live client local disk of a proxy server. The use of caching reduces access to the source server, thus saving traffic and communication time.

HTTP Knowledge Popularization series: Web server with HTTP collaboration