hi: There are two interface cards in each machine. One is fast ethernet and the other is Myrinet. I configured IP over Myrinet. each set of name is associated with a set of IP. for example: host1:Myrinet IP: 192.168.1.1 name:mnode1 Ethernet IP: 192.168.0.1 name:node1 host2:Myrinet IP: 192.168.1.2 name:mnode2 Ethernet IP: 192.168.0.2 name:node2 No matter how you configured the hostname in the config.sh, lconf can not make mnode1 talk to mnode2. Instead mnode1 is trying to talk to node2. How to ensure Myrinet IPs to talk to each other in the configuration file? Thanks! ____________________________________________________ Start your day with Yahoo! - make it your home page http://www.yahoo.com/r/hs