[j-nsp] EX9200 DHCP Relay

[Chris Jones]

My DHCP clients are all stuck in SELECTING state. Has anyone ever seen that, or maybe know what causes it?

root at DVT-EX9200> show dhcp relay binding

IP address        Session Id  Hardware address   Expires     State      Interface
0.0.0.0           18          00:25:90:3d:76:34  0           SELECTING  irb.30
0.0.0.0           19          00:25:90:3d:e5:13  0           SELECTING  irb.30
0.0.0.0           17          00:25:90:6d:f0:c3  0           SELECTING  irb.30
0.0.0.0           23          d4:be:d9:95:b6:4f  0           SELECTING  irb.16




> On Sep 16, 2014, at 3:13 PM, William McLendon <wimclend at gmail.com> wrote:
> 
> this is a working DHCP config on EX9200s — make sure you include the forward-snooped-clients all-interfaces statement, or any transit DHCP packet that traverses an interface without DHCP relay configured will be eaten by the EX9200 — its the most asinine thing in the world to have (a carryover from MX some sort of DHCP security i’m sure), but its completely undocumented it does this from what i’ve seen.
> 
>    dhcp-relay {
>        forward-snooped-clients all-interfaces;
>        server-group {
>            CAMPUS {
>                192.168.168.168;
>            }
>        }
>        active-server-group CAMPUS;
>        route-suppression {
>            destination;
>        }
>        group LOCAL-NETS {
>            interface ge-5/0/0.304;
>            interface irb.9;
>        }
>    }
> }
> 
> 
> the route-suppression destination statement also prevents it from installing access-internal host routes and permanent ARP entries for every DHCP lease.
> 
> 
> will
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Chris Jones, JNCIE-ENT #272 / JNCIP-SP
SDN Engineer
www.sdnessentials.com
Cell: 858-888-0373
E-Mail: chris at sdnessentials.com