Frame Tagging

Simon Hobson simon at
Thu Aug 15 07:11:19 UTC 2013

sthaug at wrote:
>A DHCP relay agent converts DHCP *broadcast* requests from the client
>to DHCP *unicast* requests going towards the server - and performs the
>opposite conversion for unicast replies from the server towards the
>client. I assume this is what the DHCP Helper address option on the
>Procurve does.

Not having used it on a switch, hmm I feel a test coming on ..., does it actually remove the original packet from the wire ? Ie, does it intercept and block the original broadcast packet before it gets forwarded by the switching fabric ?
I'm thinking that since the primary function of the relay agent is to relay requests to an off-segment server, in the basic case there'd be no need to actually remove the original packet - only capture and relay it. If that is the case (and it's only guesswork from me), then just adding a relay agent function to the switch won't be sufficient, you'd also need to disconnect the server from that segment/VLAN or compile the server to not use raw packets.

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