docker-proxy ipv6

ip.go

package main
//
// Run with:
// docker run -it --rm -p 8000:8000 -v $(pwd):/data debian /data/ip
//
import (
        "fmt"
        "net"
        "io"
        "net/http"
)

func getIpAddress(r *http.Request) string {
        hdrRealIp, _, _ := net.SplitHostPort(r.RemoteAddr)
        return hdrRealIp
}

func hello(w http.ResponseWriter, r *http.Request) {
        ip := getIpAddress(r)
        fmt.Println(ip)
        io.WriteString(w, ip+"\n")
}

func main() {
        http.HandleFunc("/", hello)
        http.ListenAndServe(":8000", nil)
}

test.txt

user@host:~$ curl -4 http://domain.tld:8000/
137.***.***.3
user@host:~$ curl -6 http://domain.tld:8000/
172.17.42.1