Scenario: Brand new Dell M610 blades.

Connected to the network with a 10GE uplink into a Dell PowerConnect M6220 blade switch.

DHCP server evidently working, as everything else boots / gets addresses fine.

TFTP server working fine.

Can't seem to get a DHCP address from the server.


Is there something on a blade chassis level interfering? Will I need to set up something special on the chassis? On the switch? On the blade?

  • Portfast = Enabled.
  • IP Helper = Points at our DHCP server (BUT! Shouldn't be needed, everything is somewhere on
  • DHCP Relay = Enabled
  • DHCP Snooping = Disabled

Now What?

  • 1
    What do the DHCP server logs say? You should see the DHCP exchange (On my ISC DHCP daemon, the exchange steps are DHCPDISCOVER, DHCPOFFER, DHCPREQUEST and then a DHCPACK) so that the client gets an IP address. It looks like your server isn't making it past this step (TFTP occurs after this step, so it's irrelevant for the error above). – Stefan Lasiewski Jan 31 '12 at 18:57
  • The traffic isn't getting that far. – Tom O'Connor Jan 31 '12 at 23:34
  • You mean there is nothing in the logs at all? Traffic is not making it to the server? That's good to know, because it helps to clarify your question. – Stefan Lasiewski Jan 31 '12 at 23:41
  • There's not nothing in the logs.. The DHCP works for every other physical device on the network. There's nothing blade-related there. – Tom O'Connor Jan 31 '12 at 23:49

It sounds like you might have an L3 switch in the mix that needs DHCP Forwarding configured on it.


MDMarra was closest with the suggestion of a L3 switch.

I actually solved this just now (20:20 GMT) by:

  1. Resetting the switch to factory defaults.
  2. Double-checking the cables to the fibre core switch and the patch panel.
  3. Swapping the SFP port on the Core Switch
  4. Swapping the SFP port on the Dell Blade Switch (Why this matters is beyond me, unless there's a duff port).
  5. Testing everything one more time.

Maybe you haven't enable portfast, or the Dell equivalent on the switch?

  • Portfast is enabled. – Tom O'Connor Jan 31 '12 at 18:43

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.