[Beowulf] Re: PVM on wireless...

David Mathog mathog at caltech.edu
Thu Feb 7 12:33:08 PST 2008

> From: "Robert G. Brown" <rgb at phy.duke.edu>

> However, I've just manage to figure the problem out on my own.  It is,
> after all, a firewall issue. 

Good that you sorted that out.  

A word of warning though, just yesterday I ran into a case where the
command to "turn the firewall off", didn't.  What it did instead was
wall off the machine.  This was on a vanilla Mandriva 2007.1 machine, after:

 /etc/rc.d/init.d/shorewall stop

iptables showed that the Input and Forward chains were set to DROP.
Of course the only way I could find this out was on the console of that
machine, which was luckily only about 5 feet way.  This may be what
is desired in some instances, but it wasn't what I  wanted here. 
(Plus it would suck big time if that happened on
a remotely administered machine.)  To really get rid of the firewall

  /etc/rc.d/init.d/iptables stop

was also needed.  After that iptables --list showed the expected
ACCEPT on all 3 chains and the packets that needed to get through
for the test finally did.


David Mathog
mathog at caltech.edu
Manager, Sequence Analysis Facility, Biology Division, Caltech

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