package main import ( "net" "regexp" ) func isDomain(domain string) bool { if isIP(domain) { return false } match, _ := regexp.MatchString(`^([a-zA-Z0-9\*]([a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,6}$`, domain) return match } func isIP(ip string) bool { return (net.ParseIP(ip) != nil) }