PXE/DHCP problems with a cisco switch solved

[Philipp Grau]

Hello,

Thomas and me had a short talk about PXE (not) booting HP ProLiant
servers, that are connected through a Cisco switch at the SANE
conference.

Our problem was that the DHCP server did not get any requests form the
client machine that was attempting a PXE boot. All ports were on
auto-negotiation.

Setting the link speed of both the switch port and the Ethernet Boot
Agent to "100Mbps Full" solved the problem, but that was not really
what we wanted. So we did some more investigation, and found the
following solution:

If you are experiencing the PXE/DHCP problem described above, you are
probably have VLANs configured. Disable spanning tree on the switch ports
or disable the PAgP (Port Aggregation Protocol). If both are on, you are in
trouble. 

Regards, Philipp