If the client XP computer has no network connection, the user process will be very slow. The logon speed is ok when it is connected to our domain. Is this normal? or what's the problem?

Hello Rajeev,As you stated, the logon speed is ok when it is conected to your domain. Most likely this issue is caused by searching for DC to apply user configuration group policy or logon script.You can enable environment debug logging in the client XP computer. Then check the %Systemroot%\Debug\UserMode\Userenv.logfileto seewhat happened in the logging slow process.Please refer to:How to enable user environment debug logging in retail builds of Windowshttp://support.microsoft.com/default.aspx?scid=kb;EN-US;221833Best Regards,Wilson JiaThis posting is provided "AS IS" with no warranties, and confers no rights.

Also have a look at the following guide coming directly from the Directory services team and which lists many things that can cause slow logons:http://blogs.technet.com/askds/archive/2009/09/23/so-you-have-a-slow-logon-part-1.aspxhttp://blogs.technet.com/askds/archive/2009/09/24/so-you-have-a-slow-logon-part-2.aspx