After cluster not working .................

Hi guys,

I am now able to cluster the two nodes using the following link
http://dev.esl.eu/blog/2008/09/30/set-up-clustering-in-ejabberd/

All working fine. I am able to see the second node in my first cluster.when i run the following command in second node
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erl -name ejabberd@second.example.com -mnesia extra_db_nodes "['ejabberd@first.example.com']" -s mnesia
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that time only i am able to see second node under running nodes in my first host.
When exit from the command(Close the command line)i am not able to see the second node under running nodes.

pls any one help me

thanks for Badlop for help me.pls guide me

thanks in advance
regards
alagar