To find a common way to get source IP no matter direct connection, via forward proxy, via MITM proxy, or NAT

How to test?

1. vagrant up

2. ssh to server

   cd /vagrant
   make setup-server-key
   make run-greeter-server

3. ssh to proxy

   • Forward proxy

   cd /vagrant
   make run-squidproxy

   • MITM proxy

   cd /vagrant
   make run-mitmproxy

4. ssh to client

   cd /vagrant
   make setup-server-key
   make run-greeter-server

Test result

Bridge Network

Client (172.31.1.10) > [(opt) Proxy (172.31.1.20) >] Server (172.31.1.30)

Use Case	peer	x-real-ip	x-forwarded-host	x-forwarded-for	authority
DIRECT GRPC	172.31.1.10	N/A	N/A	N/A	172.31.1.30:8081
DIRECT HTTP	127.0.0.1	N/A	172.31.1.30:8080	172.31.1.10	172.31.1.30
FWProxy GRPC	172.31.1.20	N/A	N/A	N/A	172.31.1.30:8081
FWProxy HTTP	127.0.0.1	N/A	172.31.1.30:8080	172.31.1.20	172.31.1.30
MITM GRPC	172.31.1.20	N/A	N/A	N/A	172.31.1.30:8081
MITM HTTP	127.0.0.1	N/A	172.31.1.30:8080	172.31.1.20	172.31.1.30
NGXProxy GRPC
NGXProxy HTTP	127.0.0.1	N/A	172.31.1.30:8080	172.31.1.20	172.31.1.30

NAT Network (1.160.105.176)

Client (172.31.1.10) > [(opt) Proxy (172.31.1.20) >] Server (44.204.136.57)

Use Case	peer	x-real-ip	x-forwarded-host	x-forwarded-for	authority
DIRECT GRPC	1.160.105.176	N/A	N/A	N/A	44.204.136.57:8081
DIRECT HTTP	127.0.0.1	N/A	44.204.136.57:8080	1.160.105.176	44.204.136.57
FWProxy GRPC	1.160.105.176	N/A	N/A	N/A	44.204.136.57:8081
FWProxy HTTP	127.0.0.1	N/A	44.204.136.57:8080	1.160.105.176	44.204.136.57
MITM GRPC	1.160.105.176	N/A	N/A	N/A	44.204.136.57:8081
MITM HTTP	127.0.0.1	N/A	44.204.136.57:8080	1.160.105.176	44.204.136.57
NGXProxy GRPC
NGXProxy HTTP	127.0.0.1	N/A	44.204.136.57:8080	1.160.105.176	44.204.136.57