[syslinux] tftp with pxelinux.0 from syslinux 4.10-pre17

[Gene Cumm]

On Dec 31, 2011 10:46 AM, "Christian Hesse" <list at eworm.de> wrote:
>
> Gene Cumm <gene.cumm at gmail.com> on Sat, 31 Dec 2011 09:28:16 -0500:
> > On Dec 31, 2011 7:52 AM, "Christian Hesse" <list at eworm.de> wrote:
> > >
> > > Gene Cumm <gene.cumm at gmail.com> on Fri, 30 Dec 2011 22:17:39 -0500:
> > > > On Fri, Dec 30, 2011 at 02:40, Christian Hesse <list at eworm.de>
wrote:
> > > > > http://www.eworm.de/tmp/tcpdump-syslinux-lwip-v.log
> > > > > tcpdump -i eth0 -l -n not host 172.16.0.29 -w /tmp/tcpdump.log
> > > > > Notebook A (172.16.0.1) has the pxe server, notebook B
(172.16.0.29)
> > runs
> > > > > a virtual machine, the ethernet interface is bridged to the
notebook's
> > > > > ethernet interface. Boot fails here.
> > > >
> > > > Are all of these pcap files from Notebook A?  I see this one goes
> > > > dead/deaf/ignorant after the TFTP return of file not found.
> > >
> > > Yes.
> > > But it looks nearly the same on notebook B.
> >
> > Using switch port mirroring?  I normally consider port mirroring best
when
> > possible and captures from the server next best.  How is it any
different?
>
> No switch involved... What port do you want to mirror?

Sorry, I missed that part.  Direct connect and capture in promiscuous is
equal to port mirror and capture in promiscuous (but with less other
traffic).  I need to try documenting this.

> Ok, an even more simple configuration:
> * notebook serving network boot on tap device "tap0"
> * Virtualbox virtual machine with one "Bridged Adapter" to tap0
> * virtual machine configured to boot from network
>
> And here is the log:
> http://www.eworm.de/tmp/tcpdump-syslinux-lwip.log

I'll try to look at this shortly.

> > I presume you don't really see the message of trying pxelinux.cfg/<UUID>
> > (or it just flashes).
>
> Right.

Mildly positive.

> > This sounds like the network connection is closed between receiving file
> > not found on UUID and sending the MAC request, which is extremely
different
> > from Shantanu's issue.
> >
> > Have you tried setting the DHCP option for PXELINUX path prefix to an
HTTP
> > URL yet?  It may be unlikely to help but just in case the PXE/UNDI
doesn't
> > like PXELINUX sending TFTP/UDP packets over UNDI, it might show
something
> > different.
>
> I have tried:
>
> option path-prefix code 210 = string;
> option path-prefix "http://pxe./";
>
> But pxelinux still tries to load from tftp. Does it support loading
> configuration files from http?

You also have to force feed the option as ISC-dhcpd doesn't send options
not requested by default (whose behavior I agree with;  this keeps offers
cleaner).

> > Does notebook B have a serial port?
>
> I can attach a serial port to the virtual machine, yes.

This will likely be necessary as it's the only reliable way to get the few
hundred lines of debug output that can be generated.  I used this myself to
debug and test the fix that resolved the issue noted with VMware platforms
(although only about 20 or so lines in the middle of 300-500 lines answered
the questions).  I believe this will take changing ~2-3 source files to
enable the needed debug options.

--
-Gene