Golang : Check if IP address is version 4 or 6
Problem :
Your Golang program needs to determine if a given IP address is version 4 or 6.
Solution :
Not really a fool proof solution, but it should be sufficient to detect if a given string has a decimal or colon in it. If the string has decimal as separator, then it is IP version 4 and if colon, then it is IP version 6.
Here you go :
package main
import (
"fmt"
"net"
)
func ip4or6(s string) string {
for i := 0; i < len(s); i++ {
switch s[i] {
case '.':
return "version 4"
case ':':
return "version 6"
}
}
return "unknown"
}
func main() {
var ipAddress string = "192.168.0.1"
//sanity check
testInput := net.ParseIP(ipAddress)
if testInput.To4() == nil {
fmt.Printf("%v is not a valid IPv4 address\n", testInput)
}
fmt.Printf("%s is IP address of : %s \n", ipAddress, ip4or6(ipAddress))
var ip6Address string = "FE80::0202:B3FF:FE1E:8329"
//sanity check
testInputIP6 := net.ParseIP(ip6Address)
if testInputIP6.To16() == nil {
fmt.Printf("%v is not a valid IP address\n", testInputIP6)
}
fmt.Printf("%s is IP address of : %s \n", ip6Address, ip4or6(ip6Address))
var ip6AddressURLPort string = "http://[2001:db8:0:1]:80"
//sanity check
testInputIP6URLPort := net.ParseIP(ip6AddressURLPort)
if testInputIP6URLPort.To16() == nil {
fmt.Printf("%v is not a valid IP address\n", ip6AddressURLPort)
}
fmt.Printf("%s is IP address of : %s \n", ip6AddressURLPort, ip4or6(ip6AddressURLPort))
}
Output :
192.168.0.1 is IP address of : version 4
FE80::0202:B3FF:FE1E:8329 is IP address of : version 6
http://[2001:db8:0:1]:80 is not a valid IP address
http://[2001:db8:0:1]:80 is IP address of : version 6
References :
See also : Golang : How to check if IP address is in range
By Adam Ng
IF you gain some knowledge or the information here solved your programming problem. Please consider donating to the less fortunate or some charities that you like. Apart from donation, planting trees, volunteering or reducing your carbon footprint will be great too.
Advertisement
Tutorials
+12.1k Golang : Linear algebra and matrix calculation example
+8.2k Golang : Create and shuffle deck of cards example
+18.6k Golang : How to get time from unix nano example
+6k Golang : Normalize email to prevent multiple signups example
+13.8k nginx: [emerg] unknown directive "ssl"
+13.7k Golang : Search folders for file recursively with wildcard support
+32.4k Golang : Create x509 certificate, private and public keys
+25.8k Golang : Find files by name - cross platform example
+5.3k Golang : Detect face in uploaded photo like GPlus
+4.5k Golang : Reclaim memory occupied by make() example