Hi, Sorry to bother you guys on this stupid question. last time I re-install OS for all blades to keep them the same version. after I mount, set keyless ssh, the terimnal gives the error below: [proxy:0:[email protected]] HYDU_sock_connect (./utils/sock/sock.c:174): unable to connect from "iocfccd3.aps.anl.gov" to "iocfccd1.aps.anl.gov" (No route to host) [proxy:0:[email protected]] main (./pm/pmiserv/pmip.c:189): unable to connect to server iocfccd1.aps.anl.gov at port 38242 (check for firewalls!) I can ssh from iocfccd1 to iocfccd3 without password. Should I shut down all firewalls on each server? I cannot find out where is the problem. Thank you -- Best Regards, Sufeng Niu ECASP lab, ECE department, Illinois Institute of Technology Tel: 312-731-7219