Master Internal Network Mapping with FRP: Setup, Custom Domains, and SSH Access

During the pandemic everyone discussed remote work; see Huang Dongxu's "PingCAP's 5‑year remote work practice". Below are common internal network mapping tools.

Why do internal network mapping

Accessing internal devices from the public internet is troublesome, especially for WeChat development. Devices may be behind routers or lack public IPs.

Ask the network admin to add port mapping on the router.

Buy dynamic DNS services like PeanutShell.

Use free (or paid) NAT traversal services such as natapp.

Self‑host mapping using ngrok/frp.

Why we abandoned ngrok and use frp

In 2016 we offered a free ngrok service and shared setup steps in "Angrok an internal penetration service". The setup was unfriendly, so we stopped and switched to frp.

GitHub popularity comparison

Supported protocols

frp supports http, ssh, tcp, udp, ftp and other protocols.

Getting Started

Preparation

To build a complete frp service we need:

A public‑IP ECS instance.

A domain name (optional if no DNS).

Install frp (frps) server

Download frp package.

https://github.com/fatedier/frp/releases/download/v0.31.1/frp_0.31.1_darwin_amd64.tar.gz

Extract and edit frps.ini.

[common]
bind_port = 7000     # port used by frps service
vhost_http_port = 80  # port frps listens for forwarding

Start frps service.

./frps -c ./frps.ini

Install frp (frpc) client

On the target internal machine, install client; download appropriate version for the OS.

Custom domain access to internal service

Edit frpc.ini.

[common]
server_addr = <public ECS IP>
server_port = 7000

[unique_name]
type = http
local_port = <local service port>
custom_domains = <custom domain>

Start client. ./frpc -c ./frpc.ini Access the custom domain to reach the internal service.

Use SSH to access company internal machine

Edit frpc.ini.

[common]
server_port = 7000

[unique_name]
type = tcp
local_ip = 127.0.0.1
local_port = 22
remote_port = 10022

Start client. ./frpc -c ./frpc.ini SSH into internal machine.

ssh -p 10022 [email protected]