recover old active node in ccr   

i m setting up an 2 server for mailboxserver role . and 2 server for hub+cas 
server in CCR environment. in my test environment, my active mailbox server 
goes down completely.so the passive node become active node . now i just want 
to know how to recover  that old active node . what steps should i take for 
this. 
and what happend if both two node fails (which used MNS ), will MNS capable 
to decide which node will be active or passive. 

thanks in advance.

date: Thu, 17 Apr 2008 05:56:02 -0700   author:   Gaurav