multiple relay agents between a client and an Option 82 server

[Ed Ravin]

On Mon, Apr 18, 2011 at 05:41:56PM +0200, Sergey Lukin wrote:
>    Dear all,
>    I'm trying to configure network with multiple relay agents between a
>    client and an Option 82 server. (I'm using 2 identical switches)
>    In the documentation on my switch HP ProCurve 2900 it is written
>    Note: In networks with multiple relay agents between a client and an
>    Option 82 server, append can be used only if the server supports
>    multiple Option 82 fields in a client request. [...]

I recently ran into this issue.   If you are using tagged VLANs between
your switches, you can tell the HP Procurve to not do DHCP snooping and
Option 82 insertion on packets received on tagged ports, by removing the
"dhcp-snooping vlan NN" statments from your config..  The switch
always does DHCP snooping on untagged ports in the same VLAN that has
an "ip helper" address configured, which in most cases is enough.

I was using the Option 82 "keep" settings in a test network, and was
getting duplicate DHCP requests from each intermediate switch until
I removed the "dhcp-snooping vlan ..." statement.

	-- Ed