Note: Intranet tunneling requires a public server (Linux or Windows) as the proxy.

Request: Local Machine -> Remote Proxy -> Remote Intranet Machine (or the local machine can also act as the remote intranet machine)
Return: Remote Intranet Machine -> Remote Proxy -> Local Machine

Test Environment:

Server: 211.159.16.x

Intranet Client / Test Machine: Windows PC, also used as the testing machine
 

Download and Extract:

http://mirror.cnop.net/frp/frp_0.21.0_windows_amd64.zip

Server Configuration: Delete frpc-related files, keep only the files needed for the server

Double-click the configuration file frps.ini and add the following content:

[common]
bind_port = 7000
vhost_http_port = 6081

Open cmd, navigate to the relevant directory, and run the program:

d:
cd D:/Program Files/frp_0.21.0_windows_amd64
frps.exe -c frps.ini

Client Configuration: Delete unnecessary server files

Double-click the configuration file frpc.ini and add the following content (using a web service as an example):

[common]
server_addr = 211.159.16.x
server_port = 7000
[web]
type = http        
local_port = 80
custom_domains = 211.159.16.x

Explanation:
server_addr is the server IP
server_port is the server service port; make sure it matches the server configuration
local_port is the local web port to be mapped
custom_domains is the domain or IP to be used for access

Use the same method to enter cmd and run:

d:
cd D:/Program Files/frp_0.21.0_windows_amd64
frpc.exe -c frpc.ini

Test:

http:// 211.159.16.x:6081

Server Startup Script (place in the program root directory):

@echo off

%~d0

cd %~dp0
frps.exe -c frps.ini
pause

Client Startup Script (place in the program root directory):

@echo off

%~d0

cd %~dp0

frpc.exe -c frpc.ini
pause