require 'ipaddr' module Dyndnsd class Helper def self.fqdn_valid?(hostname, domain) return false if hostname.length < domain.length + 2 return false if !hostname.end_with?(domain) name = hostname.chomp(domain) return false if !name.match(/^[a-zA-Z0-9_-]+\.$/) true end def self.ip_valid?(ip) IPAddr.new(ip) return true rescue ArgumentError return false end end end