You cannot just expect a machine to rejoin the domain, there is no utility to do this and it should never happen. Something bad is going on you should get to the bottom of. That is why are your machines leaving the domain.
Do you have any messages in the event logs prior to them losing connectivity? How did these machines get built, how were they joined? How often do you lose a machine? Does it happen to certain machines over and over, etc...
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Paul Bergson
MVP - Directory Services
MCITP: Enterprise Administrator
MCTS, MCT, MCSE, MCSA, Security+, BS CSci
2008, Vista, 2003, 2000 (Early Achiever), NT4
Microsoft's Thrive IT Pro of the Month - June 2009
http://www.pbbergs.com
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