[syslinux] Strange behavior

Roy Marantz roy.marantz at vonage.com
Thu Nov 17 07:38:01 PST 2011

On 11/16/11 7:55 PM, "Gene Cumm" <gene.cumm at gmail.com> wrote:

> On Wed, Nov 16, 2011 at 16:36, Roy Marantz <roy.marantz at vonage.com> wrote:
>> I just tried it using syslinux 4.04 on a physical machine and everything
>> worked reliably.  So I would conclude that there is some race condition
>> between vCenter 4.10  and SYSLINUX 4.04.  How close is SYSLINUX 4.10 to
>> being available or is there any plan to backport that patch to SYSLINUX
>> 4.04?
> ...
> 1) vCenter isn't really in the equation, except to provide you console
> access.  Getting familiar with the names of the 5 or so products you
> probably use can be mildly confusing with how close their names are
> and how you connect things.

You lost me on this.  What products are you referring to?  I thought I was
pretty explicit when I said I was using  vCenter 4.10 and SYSLINUX 4.04.
Should I have said that I was usings vCetner's default pxe boot code and
everything else (gpxeline.0, pxelinux.0, menu.c32) from SYSLINUX 4.04?

> 2) Your issue is not the same as the one I had with 4.10.  That issue
> was specific to 4.10.  I've had no issues with 4.04.  It sounds more
> like dropped/ignored packets for some reason.

I can understand how dropped packages would affect dhcp or tftp protocols,
but http (tcp) should handle lost, duplicate, or out of order packets
correctly.  Would you enlighten me on what failure mode you are talking

>> BTW, I was still seeing requests for menu.c32.{cbt,com,c32}.  I did "ln -s
>> menu.c32 menu.c32.c32" to work around that.

I think this is a bug in the way pxelinux.0 (or some library code from
gpxelinux.0) is handling the UI directive that causes this.  The name I
specify in the UI line is never searched for.

> On the physical machines running PXELINUX 4.04?  This has me leaning
> towards communication with a switch or your machine with the HTTPD
> dropping packets.  Try a packet capture.  A switch with port mirroring
> or a hub may also help in the physical case.  For the VM, there are
> some security options on the vSwitch.
>> I can write up my setup in detail if you guys want some documentation.  I
>> made some small changes to dhcpd.conf, apache2 conf, and a custom perl cgi
>> script to hack a pxelinux/menu config.
>> Thanks.
>> Roy
> Options that might cause it to drop packets/connections "in the name
> of security" should be examined (including a firewall).
> A: Because it messes up the order in which people normally read text.
> Q: Why is Top-posting such a bad thing?

At the expense of forcing you to read lots of duplicate information or  big
threads to understand the message.  But I won't argue email styles anymore.
Like coding, I'll follow your style.
Thanks for your help.

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