I have requirement to get macId using Applets. up to jre 6 update 21 it working properly. But in jre6 update 22 and latest versions by using loop back address or system name unble get mac address due to sucurity permissions. if I give manually all permissins jre6\lib\security\java.policy file then it is working fine. But client cannot do this about 30,000 machines as his requirement. SO please suggest me any other proggrammatic solution.