[syslinux] syslinux.efi pxeboot across multiple subnets

[Jason Matthews]

The setup I was using was in a chassis. Slot 8 of the chassis is the client
machine. It goes through Switch 1 (a Brocade switch) to the top of rack
(BNT). The mirror is in the chassis switch. Slot 3 of the same chassis is
connected to the mirror port in Switch 1.

client = 1/0/8
tcpdump = 1/0/3
to TOR = 1/0/43
1/0/8 mirrored both directions to 1/0/3

Unfortunately, I don't have access to the switch configs of the TOR
switches so I can't say how many gateways it's going through. 10.16.233.20
goes through 10.16.233.1 and 10.16.195.178 goes through 10.16.194.1. All
the switch magic after that is hidden from me.


On Sat, Nov 9, 2013 at 4:33 AM, Geert Stappers <stappers at stappers.nl> wrote:

> Op 2013-11-08 om 15:44 schreef H. Peter Anvin:
> > On 11/08/2013 03:35 PM, Geert Stappers wrote:
> > > Op 2013-11-08 om 10:48 schreef H. Peter Anvin:
> > >> Thank you for posting the pcap files, by the way.  Analyzing them in
> > >> Wireshark is so much nicer than reading the text output of tcpdump.
> > >
> > > Fetch the new capture with
> > >
> > >  wget -O pcap2.zip http://ge.tt/api/1/files/136167y/0/blob?downlad
> > >
> > > The capture[1] shows two TFTP transmissions of sles113/syslinux.efi,
> > > but nothing after that. As if syslinux.efi was crashed.
> > >
> > > [1] With a snaplength of 96 bytes or something.
> > >     Add -S0 to tcpdump to get the full network packets.
> >
> > syslinux.efi either crashed or just can't get packets out.  Either of
> > which is bad, obviously.
>
> And a thrid option, still bad: Send out packets didn't get across gateway.
>
> That is possible when the mirror port is at the same side of a gateway
> as the TFTP server is. Euh, I mean visible where I said possible.
>
> Please confirm where in the network the tcpdump is made,
> or even better: capture the packets near the booting machine.
>
> Something else: How many gateway / routers are involved?
>
>
> Groeten
> Geert Stappers
> Yes, it is good to respect the discussion order
> --
> Leven en laten leven
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