Get local IP that a given host can reach the local machine on

localaddr.go

package main

import (
	"fmt"
	"log"
	"net"
)

func localAddrForHost(host string) (string, error) {
	conn, err := net.Dial("udp", host + ":12345")
	if err != nil {
		return "", err
	}

	localAddr := conn.LocalAddr().(*net.UDPAddr)

	return localAddr.IP.String(), nil
}

func main() {
	h := "192.168.122.100"
	l, err := localAddrForHost(h)
	if err != nil {
		log.Fatalf("%v", err)
	}

	fmt.Printf("Local address for %s: %s\n", h, l)
}