Hi Sufeng, Can you ping/ssh exactly this name "iocfccd1.aps.anl.gov" from iocfccd3? [1] Antonio On Friday, June 21, 2013 10:51:50 AM Sufeng Niu wrote: 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][2]] HYDU_sock_connect (./utils/sock/sock.c:174): unable to connect from "iocfccd3.aps.anl.gov[3]" to "iocfccd1.aps.anl.gov[1]" (No route to host) [proxy:0:[email protected][2]] main (./pm/pmiserv/pmip.c:189): unable to connect to server iocfccd1.aps.anl.gov[1] 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[4] -------- [1] http://iocfccd1.aps.anl.gov [2] mailto:proxy%3A0%[email protected] [3] http://iocfccd3.aps.anl.gov [4] tel:312-731-7219