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New Member

DHCP failures after 2924->3524 upgrade

I just swapped out a bunch of 2924Cs for 3524-PWR switches preparing for a VoIP rollout. All ports are configured either as access ports for VLAN1 or as dot1q trunks for the phones on VLAN2 and daisy-chained PCs on VLAN1. All ports are configured as PortFast ports. We are finding that older PCs with ISA 10Mb NICs often (but not always) fail to get their DHCP-assigned addresses on startup. One of the PCs with a consistent problem connects thru a small Netgear Dual-Speed hub, thence to the 3524, which would seem to eliminate the 3524 from suspicion, but the problem did not exist on the 2924s. Any ideas?

New Member

Re: DHCP failures after 2924->3524 upgrade

Assuming that all other related configuration is correct (and I think since the 2924s were working fine, this is a relatively safe assumption), on the surface it looks like a negotation problem. Have you tried manually setting the speed and duplex on the ports to see if that helps? That would be my first step.

New Member

Re: DHCP failures after 2924->3524 upgrade

My thought as well, but thinking of that as step backward, we've so far just replaced the NICs with inexpensive PCI 10/100s and the problem goes away. In the one affected machine with no open PCI ports, we just told the user to do a release/renew of his IP and it seems to bypass the problem, if not solve it.

We're now seeing another problem -- in the 4 days the 3524s have been up, we've had 2 NICs fail. Modern ones, same type, came in Dell laptops. Stay tuned.

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