[Beowulf] Re: question for licensed software users

[Daniel Pfenniger]

Hi,

I encountered also a NIC problem with Maple flexlm.  Flexlm checks
the existence of the original eth0 NIC present at Maple install time.
This interface was later bad, so a second one was added and
used instead of eth0.  But then Maple was then prevented to start by
flexlm.  After some search it was found that after each reboot one has
to initialize eth0 once (ifconfig eth0 ... up), even if disabled later
in order to satisfy flexlm.

No need to say that the lost time finding the cause of flexlm disfunction
was yet another argument to hate licensed software.

	Dan


David Mathog wrote:
>> I have had eth0 and eth1 "change" identities as I patch the OS or add 
>> ethernet cards. 
> 
> Recent versions of Linux, such as Mandriva 2007.1, have an /etc/iftab
> and/or /etc/udev/rules.d/61-net_config.rules files.  Both of these
> associate one specific MAC with eth0, eth1, etc.. 
> The original intent was noble - they were trying to provide a
> way to allow eth0 to always be the wired and eth1 the wireless
> network connection, for instance.  However if these files
> get the least bit out of sync with the actual hardware
> all hell can break loose.  For instance, if one clones a single NIC
> machine that uses these mechanisms the MAC won't match, eth0 won't be
> used and a new eth1 will be magically created.  Unfortunately
> the firewall doesn't know about eth1 and everything network
> related then breaks.  Result, most likely the machine will hang
> during boot.  Others have reported machines which create a new
> eth# device at each boot, abandoning all the previous ones.  The general
> fix for these sorts of bugs is to delete both of these files, and
> at the next boot the udev file will be recreated and will match the
> hardware.  I have not seen a need for /etc/iftab and just leave it deleted.
> 
> Now, back to Joe's problem, for the linux machines that are having
> flexlm problems, if the nature of the problem is that eth0 and eth1
> are swapping around at random, and those distros have these mechanisms,
> be sure these two files exist and are configured properly so that
> eth0 and eth1 are rigidly mapped to fixed MAC addresses.
> 
> Regards,
> 
> David Mathog
> mathog at caltech.edu
> Manager, Sequence Analysis Facility, Biology Division, Caltech
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