What is the difference between proxy server and NAT server?

Clients using private IP in the internal LAN can directly obtain www services through proxy or NAT. Is there any difference between NAT and proxy.

Function of NAT server: just like the data mentioned in Chapter 9, the NAT function of Linux is mainly through packet filtering, and uses the NAT table of iptables for IP camouflage (SNAT), a way for clients to go anywhere on the Internet by themselves. The main operation behavior is in the second, third and fourth layers of OSI seven layer protocol. Because it is through packet filtering and camouflage, the port number (layer 4) that can be used by the client is more flexible;

Function of proxy server: it mainly provides network proxy tasks through the proxy service program (daemon). Therefore, whether the proxy can perform some work is related to the program function of the service. For example, if your proxy does not provide mail or FTP proxy, your client cannot obtain these network resources through the proxy. The main operation behavior is in the application layer of OSI seven layer protocol (the so-called "higher-order" means)

Nat server is analyzed by the underlying network. As for what packets are used through NAT, NAT doesn't care about it!

As for proxy, it is mainly achieved by the functions of a daemon, so it must meet the requirements of the daemon in order to achieve some functions.