[PLUG] Troubleshooting DHCP...

[Mike Connors]

Michael Robinson wrote:
> I wonder if being a switch it was blocking the dhcp replies? 
Switches don't block broadcast protocols like DHCP. Routers do and if 
DHCP traffic
has to traverse a different network than a DHCP proxy must be configured.

However, there are a couple of cases where dhcp requests/replies could 
be inadvertently
blocked.

1. The DHCP client and dhcp server are on different VLANs.

2. Spanning Tree port configuration is another. With regular spanning 
tree (8021.d),
the switch port could be in blocking mode while the spanning tree is 
being mapped out and
therefore any DHCP traffic will not pass thru the port. As best practice 
we always
configured the switch ports with rapid spanning tree (802.1w), so that 
spanning tree convergence
happened faster and didn't impact dhcp requests.