Golang : Get local IP and MAC address

This is a short program on how to get the local IP address, search for the correct network interface hardware name and get the MAC address. Remember, this example is not able to get MAC address of remote/client machine. ;-)

Here you go!

getlocalIPandMACaddr.go

 package main

 import (
 "fmt"
 "net"
 "os"
 "strings"
 )

 func main() {

 //----------------------
 // Get the local machine IP address
 // https://www.socketloop.com/tutorials/golang-how-do-I-get-the-local-ip-non-loopback-address
 //----------------------

 addrs, err := net.InterfaceAddrs()

 if err != nil {
 fmt.Println(err)
 }

 var currentIP, currentNetworkHardwareName string

 for _, address := range addrs {

 // check the address type and if it is not a loopback the display it
 // = GET LOCAL IP ADDRESS
 if ipnet, ok := address.(*net.IPNet); ok && !ipnet.IP.IsLoopback() {
 if ipnet.IP.To4() != nil {
 fmt.Println("Current IP address : ", ipnet.IP.String())
 currentIP = ipnet.IP.String()
 }
 }
 }

 fmt.Println("------------------------------")
 fmt.Println("We want the interface name that has the current IP address")
 fmt.Println("MUST NOT be binded to 127.0.0.1 ")
 fmt.Println("------------------------------")

 // get all the system's or local machine's network interfaces

 interfaces, _ := net.Interfaces()
 for _, interf := range interfaces {

 if addrs, err := interf.Addrs(); err == nil {
 for index, addr := range addrs {
 fmt.Println("[", index, "]", interf.Name, ">", addr)

 // only interested in the name with current IP address
 if strings.Contains(addr.String(), currentIP) {
 fmt.Println("Use name : ", interf.Name)
 currentNetworkHardwareName = interf.Name
 }
 }
 }
 }

 fmt.Println("------------------------------")

 // extract the hardware information base on the interface name
 // capture above
 netInterface, err := net.InterfaceByName(currentNetworkHardwareName)

 if err != nil {
 fmt.Println(err)
 }

 name := netInterface.Name
 macAddress := netInterface.HardwareAddr

 fmt.Println("Hardware name : ", name)
 fmt.Println("MAC address : ", macAddress)

 // verify if the MAC address can be parsed properly
 hwAddr, err := net.ParseMAC(macAddress.String())

 if err != nil {
 fmt.Println("No able to parse MAC address : ", err)
 os.Exit(-1)
 }

 fmt.Printf("Physical hardware address : %s \n", hwAddr.String())

 }

Sample output:

Current IP address : 192.168.1.65

------------------------------

We want the interface name that has the current IP address

MUST NOT be binded to 127.0.0.1

------------------------------

[ 0 ] lo0 > ::1/128

[ 1 ] lo0 > 127.0.0.1/8

[ 2 ] lo0 > fe80::1/64

[ 0 ] en3 > fe80::1aa6:f7ff:fe16:e80b/64

[ 1 ] en3 > 192.168.1.65/24

Use name : en3

------------------------------

Hardware name : en3

MAC address : 18:a6:f7:16:e8:0b

Physical hardware address : 18:a6:f7:16:e8:0b

References:

https://www.socketloop.com/tutorials/golang-how-do-I-get-the-local-ip-non-loopback-address

http://grokbase.com/t/gg/golang-nuts/13cf1dcxhs/go-nuts-getting-ip-address-and-hardware-address-in-golang