Forward proxy and reverse proxy

Forward agent and reverse agent

Forward agency

The forward proxy is that the client knows the address of the server , When sending a request, the client needs to know the information of the target server , It's usually server ip And port , Users and servers cannot communicate directly for various reasons , Forward proxy can be used , Users send requests to their own proxy server , The proxy server then sends the data to the target server , For example, we use some fanxiang Software , Is the forward proxy used . Use forward proxy , Client's HTTP The request can be forwarded to a server that was previously disconnected from the client network .

Reverse proxy

Reverse proxy means that the client does not know the address of the target server , The user sends a request to the proxy server , The proxy server sends the request to the real server , For example, the client requests the domain name , After the domain name, many servers carry out load balancing , This is reverse proxy .nginx It is a software that can realize reverse proxy .

The forward proxy hides the information of the client , The reverse proxy hides the information of the server .

Reverse agents are transparent to the outside , Users do not know whether they are accessing a proxy server . Using reverse proxy can improve the security of internal server , It can also speed up access to internal servers .

nginx In addition to reverse proxy, it also has the function of load balancing , What we use is nginx Of upstream Instructions , By default, the load is distributed by polling ,

summary

Forward agent and reverse agent are two different agents , The forward proxy is that the client must know the address information of the server , Through forward proxy , Clients can access servers that cannot communicate . Reverse proxy means that the client does not know the address of the target server , User sends request to proxy server , But the client does not know that this is a proxy server , There are multiple servers under the proxy server for load balancing .