Hello everyone, After solving my first ssh_exchange_identification problem, I feel embarrassed to ask my another problem... :'((
I got some "*ssh: connect to host XXX.XXX.XXX.XX port 22: connection timed out*" errors when I mpirun over 2000 times almost at the same time. --- my bash shell script file : for (( index=0; index<2000 ; index++)) do (time mpirun --hostfile my_hostfile openMPI_test &) >> file 2>&1 done --- * * *But not "always" got this problem, just "often"*.(It seldom works well.) *In addition, the amount of "timed out" error in each test are different*. (In 2000 times, this error happened between 0~200 times) I try to google it, but I can't find anyone have this ssh problem when he/she use a lot of ssh connections... So I think maybe someone here have had the same problem as mine. ---------------------------------------------------------------------------------- The following are some of my settings that I have tried to change : 1. net.ipv4.tcp_fin_timeout=180 http://askubuntu.com/questions/21182/how-to-change-the-default-timeout-of-internet-connection 2. sudo iptables -A INPUT -p tcp --dport ssh -j ACCEPT http://www.serkey.com/ubuntu-ssh-connection-timed-out-due-to-firewall-behgct.html ---------------------------------------------------------------------------------- but these changes still didn't solve my problem... I still can't figure out where is the problem and are there some potential problems :((( If someone here have any idea about this situation ,or have had the same problem as mine? Is it my *machine problem* or *system problem*? Or *OpenMPI* can't let me do something like this? Really hope someone can give me a hand .. Thank you all very very very much!! Best Wishes, Jen