DNS Forward Proxy

A DNS forward proxy is a DNS query that a client performs through a proxy server to hide the client's true IP address. The forward proxy server obtains resources on the Internet on behalf of the client, and the client sends a request to the proxy server, which then sends a request to the Internet to obtain the resources. In DNS forward proxy, the client sends the DNS query request to the proxy server, which in turn performs the query through its own DNS server and returns the query result to the client.

The following is sample code for a simple DNS forward proxy:

“`
import socket

def dns_forward_proxy(query, proxy_ip).
dns_port = 53
proxy_server_address = (proxy_ip, dns_port)
client_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
client_socket.sendto(query, proxy_server_address)
response, _ = client_socket.recvfrom(4096)
client_socket.close()
return response

# Usage Example
query = b'www.example.com' # DNS query request
proxy_ip = '192.168.1.1' # proxy server IP address
response = dns_forward_proxy(query, proxy_ip)
print("DNS query result: ", response)
“`

DNS Reverse Proxy

DNS Reverse Proxy is a reverse DNS query performed by a client through a proxy server to hide the client's real IP address. The reverse proxy server performs DNS queries on behalf of the server side for resolving IP addresses into domain names. In DNS reverse proxy, the client sends a query request to the proxy server, which then performs a reverse query through its own DNS server and returns the query result to the client.

The following is sample code for a simple DNS reverse proxy:

“`
import socket

def dns_reverse_proxy(ip, proxy_ip).
dns_port = 53
proxy_server_address = (proxy_ip, dns_port)
query = ip.encode() # Encodes IP address into a stream of bytes
client_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
client_socket.sendto(query, proxy_server_address)
response, _ = client_socket.recvfrom(4096)
client_socket.close()
return response.decode() # Decode the query result into a string domain name

# Usage Example
ip = '192.168.1.1' IP address that # needs to reverse-query
proxy_ip = '8.8.8.8' # proxy server IP address
domain = dns_reverse_proxy(ip, proxy_ip)
print("Reverse query result: ", domain)
“`

The above is a brief introduction and sample code of DNS forward proxy and reverse proxy. With DNS proxy, clients and servers can hide their real IP addresses to protect network security. DNS proxy has a wide range of uses in practice, and can effectively protect user privacy and network security.