Option 82 problem

[Simon Hobson]

Александр Сандецкий <alexander.sandetsky at gmail.com> wrote:

> Actually I do not fully understand how it works. My hardware vendor say me that Option 82 MUST be configured on the edge (client access ) switches but you says (as I can understand) that it must be configured somewhere on the "main" (core) ROUTER, not every switch. Your concept more prefferable for me.

I suspect something has been lost in translation because you DO NOT NEED OPTION82 AT ALL for DHCP to work. You do not need it on edge switches, you do not need it on a core switch.

To clarify a bit ...
treat each VLAN as if it was a separate LAN - conceptually think of a VLAN enabled switch as a stack of "simple" switches. At some point, you need a router to link those networks together - but instead of needing a router with lots of ports (one per network), when using VLANs you can combine all the VLANs down one cable with the ports on each end in trunk mode.
Once you have the basics working (any device can reach any other device, firewall/access rules permitting, then you can consider DHCP. The only requirement there is that the DHCP server has a connection to at least one network (it can directly connect to more than one), and any network not directly connected to the DHCP server needs a Relay Agent to pick-up broadcasts from the clients and forward them to the server (and relay replies back again).

Simon