Slow DHCP with dynamic vlans
I’m looking for some help with a slow DHCP problem.
We’re using mac-based authentication, procurve switches and IAS. 30 vlans dynamically allocated, the 30 subnets managed by server 2008 DHCP.
Everything works fine except DHCP is slow, not hideously slow, but can be 10 to 30 seconds or so. This was never a real problem and got put on the back burner; but we’re now running a few thin clients which ask for an address twice during boot (one for pxe, one for the thinclient os) and so its time to pin it down.
In a nut shell,
If a machine is put in a vlan dynamically then DCHP is slow.
If the same machine is forced (port untagged) into a vlan then DHCP works as it should.
IAS validates the machines immediately so the delay isn’t there (dhcp is slow even if I randomly /release /renew after a while).
There’s nothing obvious shouting out of the DHCP logs – though I haven’t been through them with a fine tooth comb.
I’ve had a Google around and nothing stands out.
DMcCoy, I think we have a similar setup to you; did you experience anything like this?
Anyone got any ideas?
Edit: just found a slightly later firmware for the 2626’s (the changes log doesn’t mention fixing a dhcp problem but you never know…), I'll try that on monday...