[c-nsp] Setting relay agent IP on 4500

[Phil Mayers]

On 28/07/17 22:12, Jason Lixfeld wrote:
> Hi all,
>
> I’ve got a 4500 Sup7L-E running 15.2(2) acting as a DHCP relay with
> clients directly connected to it.  The client interfaces on this
> relay are in VRFs, and the helper is in the global table.
>
> The issue is the 4500 stamps the relay agent IP in the DISCOVER as
> being the incoming interface IP where the DISCOVER was received,

By relay agent IP do you mean giaddr in the bootp header? If so, this is 
required - that's how DHCP servers discover the source subnet.

You'd need support at the DHCP server side to map giaddr to a different 
reply IP.

I believe ISC dhcpd lacks this but the newer Kea might have it?