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

[Christian Hesse]

Gene Cumm <gene.cumm at gmail.com> on Sat, 31 Dec 2011 11:30:33 -0500:
> 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).

Ah, got it. Why does pxelinux not request it?

But it results in the same situation. /pxelinux.cfg/<uid> is not found, the
server returns a 404 to the client. The client then again hangs
with /pxelinux.cfg/<mac>.

http://www.eworm.de/tmp/tcpdump-syslinux-lwip-http.log

> > > 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.

Let me know what to do and I will test it.
-- 
Schoene Gruesse
Chris