[c-nsp] Setting relay agent IP on 4500

[Nathan Lannine]

On Jul 28, 2017 5:12 PM, "Jason Lixfeld" <jason at lixfeld.ca> 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, which is in a
VRF.  As such, the DHCP server tries to send the OFFER to that IP, but it’s
not reachable due to it being in a VRF, and is subsequently dropped
upstream.


Does the "global" argument not accomplish this?

I.e. "ip helper-address global <address>"

That's how I read this:
http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipapp/command/iap-cr-book/iap-i1.html#wp1413119578

Of course the above is more clear in it's description of using the "vrf"
argument.

- Nathan