[c-nsp] PXE not working on Cat2948

[Alexander Clouter]

Jens Neu <jens.neu at biotronik.com> wrote:
> 
> I have a Catalyst 2948G which seems to keep PXE boot from working 
> properly. This one Cat2948 is the only Layer 2 device between the DHCP/PXE 
> boot server and the PXE client - both are directly connected and share a 
> /24. PXE boot is not working at all, and DHCP is unbearably slow, for no 
> apparent reason. Both PXE Server and Client(s) are various IBM xSeries 
> using the onboard GBit interfaces.
> Now the fun stuff: when I put a second Layer 2 device between the Cat 2948 
> and the PXE client, it is magically working.
> Means: PXE Server -> Cat 2948 -> "some cheap Netgear Office switch" -> PXE 
> Client == works. In fact, any additional Layer 2 device that appears 
> between PXE Client and the Cat 2948 scares the problem away.
> 
> Anyone seen this before? Any hints where to start looking? The switch 
> looks as follows:
>
.....'spanning-tree portfast default'?

The PXE times out before the STP action has finished and the port is in 
blocking mode for the duration.  You should also consider 'spanning-tree 
portfast bpduguard/filter default' too.

Cheers

-- 
Alexander Clouter
.sigmonster says: That's what she said.