IP Echo
A small Go web service like ifconfig.me: call it from a browser, curl, or another service and it tells you what IP address the server sees.
What It Teaches
net/httprouting with the standard library.- Reading configuration from environment variables.
- Extracting a client IP safely from
RemoteAddr. - Optional proxy header support for deployments behind Nginx, Caddy, or a load balancer.
- Table-focused tests for request parsing and HTTP handlers.
Run
go run ./cmd/ipecho
The service listens on :8080 by default.
curl.exe http://localhost:8080/
curl.exe http://localhost:8080/ip
curl.exe http://localhost:8080/json
curl.exe http://localhost:8080/headers
curl.exe http://localhost:8080/user-agent
Use another port:
$env:ADDR = ":9090"
go run ./cmd/ipecho
Trust reverse proxy headers:
$env:TRUST_PROXY_HEADERS = "true"
$env:TRUSTED_PROXY_CIDRS = "127.0.0.1/32,::1/128"
go run ./cmd/ipecho
Only enable TRUST_PROXY_HEADERS when your service is behind a proxy you control. Keep TRUSTED_PROXY_CIDRS limited to that proxy; otherwise, anyone can spoof forwarded IP headers.
Endpoints
| Endpoint | Response |
|---|---|
GET / |
Browser dashboard or plain text client IP for CLI requests |
GET /ip |
Plain text client IP |
GET /json |
JSON request metadata |
GET /headers |
Plain text request headers |
GET /user-agent |
Plain text user agent |
GET /healthz |
Plain text health check |
GET /favicon.ico |
Embedded favicon |
Test
go test ./...
Production
See:
Regenerate icon assets and the Windows executable resource:
go generate ./...