[j-nsp] Helper bootp: Where to configure? (J2320, 9.1R1.8)

[Hendrik Kahmann]

Hello,

we tried to configure a bootp helper on a Juniper J2320 with Junos 9.1R1.8.

At first we started to configure the helper under the routing-instance (vrf)
via the following configuration:

vrf-yellow {
	instance-type vrf;
	interface ge-0/0/0.423;
	route-distinguisher xxx:xxx;
	vrf-target target:xxx:xxx;
	vrf-table-label;
	forwarding-options {
		helpers {
			bootp {
				server 1.2.3.4;
			}
		}
	}
}

With this configuration, no client connected to an interface connected to
interface ge-0/0/0.423 was able to get an address delivered by the remote
dhcp-server. The dhcp-server is reachable from the network configured in
ge-0/0/0.423.

As a workaround we tried to delete the section forwarding-options from the
routing-instance and put it into the global forwarding options, referreing
to the routing-instance:

vrf-yellow {
	instance-type vrf;
	interface ge-0/0/0.423;
	route-distinguisher xxx:xxx;
	vrf-target target:xxx:xxx;
	vrf-table-label;
}

forwarding-options {
	helpers {
		bootp {
			server 1.2.3.4 routing-instance vrf-yellow;
		}
	}
}

>From this point the dhcp-helper was working fine. What is the difference
between configuring the bootp helper inside the routing-instance and putting
it into the global forwarding options? I can't find any differences within
the documentation. Is there a difference, which ip-address (wan or lan) is
used as the source-address for the unicast-request forwarded to the
dhcp-server?


Kind regards,

Hendrik