On Fri, Nov 6, 2009 at 2:39 AM, Jeff Squyres <jsquyres_at_[hidden]> wrote:
> On Nov 5, 2009, at 11:28 AM, Lee Amy wrote:
>> I remembered MPI does not count on TCP/IP but why default iptables
>> will prevent the MPI programs from running? After I stop iptables then
>> programs run well. I use Ethernet as connection.
> Note that Open MPI *can* use TCP as an interface for MPI messaging. It
> definitely uses TCP for administrative control of MPI jobs, even if TCP is
> not used for MPI messaging. Open MPI therefore basically requires the
> ability to open sockets between all nodes in the job on random TCP ports.
> Your could probably configure iptables to "trust" all the machines in your
> cluster (i.e., allow TCP sockets to/from random ports) but disallow most
> (all?) TCP connections from outside your cluster, if you wanted to...?
> Jeff Squyres
> users mailing list
Thanks. And actually I don't know if I need to disable iptables to run
MPI programs properly. Obviously from your words Open MPI will use
random ports so how do I set up in iptables then let trusted machines
open their random ports?