Why doesn't the HTTP proxy have a DNS request?

In the web world, HTTP proxy is a common tool used to optimize and manage web traffic. However, sometimes we find that HTTP proxies do not handle DNS requests, which confuses many people. In this article, we will delve into why HTTP proxies don't have DNS requests and reveal the reasons why.

Understand the basic workings of the HTTP proxy

To understand why the HTTP proxy does not handle DNS requests, you first need to understand the basic working principle of the HTTP proxy.The HTTP proxy acts as an intermediary server responsible for forwarding HTTP requests and responses between the client and the target server. The client sends the HTTP request to the proxy server, which forwards the request to the target server and returns the response to the client.

Role of DNS requests

DNS (Domain Name System) plays an important role in network communications. It is responsible for translating human-readable domain names (e.g. example.com) into machine-readable IP addresses (e.g. 192.0.2.1). Typically, DNS requests are resolved locally at the client, which sends a request to a DNS server to obtain an IP address.

Separation of HTTP proxies and DNS requests

HTTP proxies focus on request and response forwarding at the HTTP protocol level and do not involve DNS resolution. The reason for this is that DNS resolution is usually done before the HTTP request is sent. The client already knows the IP address of the target server when it sends the request to the HTTP proxy, so the proxy does not need to perform DNS resolution.

It's like you're going to a friend's house as a guest, and you've looked up the address of your friend's house before you leave. When you get to the bus stop (HTTP proxy), you just tell the driver (proxy server) where you're going, without the driver having to look up the address for you.

How proxy servers handle requests

When a client sends a request through an HTTP proxy, it contains the full URL of the target server (e.g. http://example.com). The proxy server uses this URL to determine the target of the request without DNS resolution. The proxy server simply forwards the request to an IP address that is already resolved.

HTTPS Proxy and DNS Requests

In the case of an HTTPS proxy, the client typically uses the CONNECT method to establish a tunnel connection. At this point, the client is still responsible for DNS resolution because the proxy simply forwards the encrypted traffic to the destination server.The HTTPS proxy handles DNS requests in a similar way to the HTTP proxy, relying on the client for resolution.

summarize

The main reason that HTTP proxies do not handle DNS requests is that DNS resolution is usually done by the client and the proxy server focuses on forwarding requests and responses. Understanding this helps us to better understand how HTTP proxies work and make more informed choices when using them.

Hopefully, through this article, you have a clearer understanding of the relationship between HTTP proxies and DNS requests, and can better utilize the advantages of HTTP proxies in practical applications.