Hi!
Finally, it worked.
I opened the redhat-config-securitylevel (lokkit on the machines that
didnt have that), and changed the settings from 'Enable Default
Firewall' to 'Customize' and selected the services I needed. (ssh).
I also had to enable the 'trust eth0' box to make it work.
Even with the default firewall settings, it was letting me ssh without a
password, so Im not sure what changed. (presumably the default is 'dont
trust all packets frm eth0' which got changed to 'trust eth0'.
Im not sure abt. the effect 'trust eth0' would have on the security, but
I get it from some googling, that it should be okay so long as the
machine is not directly connected to the internet. (through a modem for
eg.), but is connected through a switch..which brings in play some
security at the network level.
Thanks,
Aditya
On Mon, 2005-02-14 at 08:59, Jeff Squyres wrote:
> On Feb 13, 2005, at 1:05 PM, Aditya Datey wrote:
>
> >> - Did you confirm that LAM was getting the right IP address for coral?
> > Yes , in a way that none of the messages show something like 127.0.0.01
> > which i found was a common error on the list archives. All the messages
> > show the correct ip for that machine.
>
> Ok, good.
>
> >> - You might want to check with local system administrators to see if
> >> any firewalls are in place between the machines (e.g., at the router
> >> or
> >> switch level)
> > I checked with the friendly neighbourhood sysadmin, and got it that
> > there was nothing that would prevent opening of ssh on random sockets.
>
> Be careful not to mix your metaphors here (so to speak). ssh and
> random sockets (at least in a LAM context) are two different things.
> LAM can use ssh, but it will only use ssh on whatever your default
> ports are (unless you specify a -p argument in $LAMRSH, for example).
> LAM does require random sockets to be able to be used between all
> nodes, but that is unrelated to rsh or ssh.
>
> > This is verified by the fact that I can boot LAM successfully on 4 of
> > the 10 machines Im trying to get it working on.
>
> Ok. So this machine that you're having a problem with is a 5th machine
> that you'd like to add to the mix?
>
> > Now the 4 working machines are a heterogenous mix, kernel and RH
> > version
> > wise. But all run LAM 7.0.6. None of the machines are older than RH8,
> > and most of them have the 2.4.22 linux kernel.
> > Now when I compiled the kernels for the machines, it is possible that I
> > selected different things (to get the sound card working etc.) on the
> > machines.
> >
> > ** So one reason I can think of for why it is working on some but not
> > all machines, is that LAM needs something in the kernel that I did not
> > put in ??
>
> No, LAM does very little in the kernel -- just system calls through
> libc, etc. (unless you're using Myrinet or Infiniband, but even then,
> we're using the user-level access libraries -- LAM has no
> kernel-specific code). So if your kernels are slightly different, LAM
> won't care.
>
> The most important aspect is to have the same version of LAM natively
> compiled on each machine. Check out the heterogeneity questions in the
> FAQ for more details.
>
> --
> {+} Jeff Squyres
> {+} jsquyres_at_[hidden]
> {+} http://www.lam-mpi.org/
>
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