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Subject: Re: [OMPI users] mpiexec hangs - new install
From: James (jamesqf_at_[hidden])
Date: 2010-07-25 16:08:05

On Sat, 24 Jul 2010 16:31:12 -0700, Ralph Castain <rhc_at_[hidden]> wrote:

> On Jul 24, 2010, at 4:40 PM, James wrote:
>> OK, that's the problem. I turned the firewall off on both machines, and
>> it works.
>> Now the question: how do I fix it? I searched through the archives, and
>> found that it seems to be a pretty common problem. Unfortunately, I
>> didn't
>> see a solution that I could understand. (I'm not a sysadmin, just a
>> person
>> trying to do some programming.)
>> I have a couple of machines on a local net, with IP addresses in the
>> range. There's a router at, which is
>> connected
>> to the internet via a cable mode. So how do I set up my system so my
>> local machines can do whatever talking between themselves that's needed
>> by
>> OpenMPI, while still having a firewall between my system and the outside
>> world?

Here's what seems to be a solution that works for SuSE. May be something
similar for other systems:

   1) Edit the file /etc/sysconfig/SuseFirewall2
   2) Look for the keyword FW_TRUSTED_NETS
   3) Add the IP addresses of your internal machines there. The format
      for multiple machines is wierd: "" means all machines
      in 192.168.10.x. There doesn't seem to be any way to specify a
      range, like .100 to .110.
   4) Add the lines FW_SERVICES_TRUSTED_TCP="1:65535" and
   5) Save the file. Bring up Yast2, and use it to stop and restart the

Hope this is useful, as it took about 10-15 hours of my time, spread over a
week or so, to figure it out.

> Most routers provide their own internal-to-external firewall - you might
> check its setup and see. If it does, then you don't need to also have
> one on your individual machines.

Seems to be the same problem as with the firewalls on the machines. That
is, there appears to be a firewall, but the little information in the
manual or online help assumes that you already have an expert sysadmin
level of knowledge.