Syslinux - Jul 2013 - pxechn.c32 does not do TFTP

On Jul 16, 2013 8:13 AM, "Victor Sudakov" <vas at
mpeks.tomsk.su> wrote:
>
> Gene Cumm wrote:
> > >>
> > >> Did you try without "-o 66..."?  Any chance for a
packet capture
from a
> > >> mirrored port or the dhcpd+tftpd-old+tftpd-new+dnsd?
> > >
> > > OK, I have tried the following:
> > >
> > > label WDS
> > >  menu LABEL ^4. Windows Deployment Service
> > >  com32 pxechn.c32
> > >  append wds01-sibptus.sibptus.transneft.ru::boot\x86\wdsnbp.com 
-W
> > >
> > > and it *does* work for the majority of PXE clients. The packet
dump is
> > > here: http://zalil.ru/34637868
> > >
> > > You can see from the dump that the client first queries DNS for
the IP
> > > address of wds01-sibptus.sibptus.transneft.ru (around frame 829)
and
> > > then downloads wdsnbp.com from 10.14.140.128.
> > >
> > > This setup does not work on VirtualBox'es PXE client, perhaps
because
it
> > > cannot do DNS lookups.
> >
> > Unfortunately, in my testing, I can't see any difference with and
> > without the -o.
>
> The -o in my case has turned out to be irrelevant.
>
> > The big thing I notice is just that since 5.10, the
> > code in pxelinux.0 does DNS queries for specific calls rather than a
> > dotted quad conversion first.
>
> That *was* relevant. It did not work until I replaced the dotted quad
> address with the DNS name. Thank you. I think a change in the
> documentation is due.
It's actually a bug in the core.

--Gene

Gene Cumm wrote:
> > > The big thing I notice is just that since 5.10, the
> > > code in pxelinux.0 does DNS queries for specific calls rather
than a
> > > dotted quad conversion first.
> >
> > That *was* relevant. It did not work until I replaced the dotted quad
> > address with the DNS name. Thank you. I think a change in the
> > documentation is due.
> 
> It's actually a bug in the core.
This bug has an unpleasant consequence.

The Oracle VirtualBox 4.2.16 PXE impementation does not request Option 6 
from the DHCP server, so it does not receive Option 6 in the DHCP
offer, so no DNS servers are available to pxelinux, therefore it
cannot resolve the WDS server's IP address, which breaks everything.

Can we get rid of this dependency on DNS?

-- 
Victor Sudakov,  VAS4-RIPE, VAS47-RIPN
sip:sudakov at sibptus.tomsk.ru

On Fri, 19 Jul, at 04:24:52PM, Victor Sudakov wrote:
> Gene Cumm wrote:
> > > > The big thing I notice is just that since 5.10, the
> > > > code in pxelinux.0 does DNS queries for specific calls
rather than a
> > > > dotted quad conversion first.
> > >
> > > That *was* relevant. It did not work until I replaced the dotted
quad
> > > address with the DNS name. Thank you. I think a change in the
> > > documentation is due.
> > 
> > It's actually a bug in the core.
> 
> This bug has an unpleasant consequence.
> 
> The Oracle VirtualBox 4.2.16 PXE impementation does not request Option 6 
> from the DHCP server, so it does not receive Option 6 in the DHCP
> offer, so no DNS servers are available to pxelinux, therefore it
> cannot resolve the WDS server's IP address, which breaks everything.
> 
> Can we get rid of this dependency on DNS?
 
Can you try 6.02-pre7, available here,

    https://www.kernel.org/pub/linux/utils/boot/syslinux/Testing/6.02/

and see whether your issue is fixed?

-- 
Matt Fleming, Intel Open Source Technology Center