This article explains how to configure bootp for virtual router (VR) to VR functionality using Logical Tunnel Interface (lt-). This is when the client facing interface is on one virtual router and the external DHCP server resides on a different virtual router. There are a couple of ways of having bootp handle this type of configuration, but this article will use lt- interfaces to accomplish this.

Goal: provide a configuration example to assist customers having DHCP clients in one virtual router and access to the DHCP server is through a different virtual router. This can be accomplished using logical tunnels to route from the DHCP server RI and the Client RI.

The following is a configuration example showing that DHCP clients in RI Clients will be able to receive a leased IP address from a DHCP server which is located externally from a RI Server using a logical tunnel.

Topology:
Client facing Interface – ge-1/3/9.100
Server facing interface – ge-1/0/0.0

Tunnel Interface configuration:
lab@MX80-user# show chassis  
aggregated-devices {
    ethernet {
        device-count 15;
    }
}
fpc 0 {
    pic 0 {
        tunnel-services {
            bandwidth 1g;
        }
    }
lab@MX80-user# show interfaces lt-0/0/10     
unit 100 {
    encapsulation ethernet;
    peer-unit 200;
    family inet {
        address 39.39.39.2/24;
    }
}
unit 200 {
    encapsulation ethernet;
    peer-unit 100;
    family inet {
        address 39.39.39.1/24;
    }
}
	

[lab@MX80-user# run show configuration interfaces ge-1/3/9 
vlan-tagging;
unit 100 {
    description BOOTP-CLIENT;
    vlan-id 100;
    family inet {
        address 25.25.25.1/24;
    }
}
lab@MX80-user# show interfaces ge-1/0/0   
unit 0 {
    description TO-DHCP-SERVER;
    family inet {
        address 150.150.150.1/24;
    }
}

lab@MX80-user# show routing-instances 
CLIENT {
    instance-type virtual-router;
    interface lt-0/0/10.100;
    interface ge-1/3/9.100;
    interface lo0.100;
    routing-options {
        static {
            route 41.41.41.0/24 next-hop 39.39.39.1;
            route 150.150.150.0/24 next-hop 39.39.39.1;
        }
    }
}
SERVER {
    instance-type virtual-router;
    interface lt-0/0/10.200;
    interface ge-1/0/0.0;
    interface lo0.200;
    routing-options {
        static {
            route 40.40.40.0/24 next-hop 39.39.39.2;
            route 25.25.25.0/24 next-hop 39.39.39.2;
        }
    }
}

CLIENT.inet.0: 7 destinations, 7 routes (7 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

25.25.25.0/24      *[Direct/0] 02:51:16
                    > via ge-1/3/9.100
25.25.25.1/32      *[Local/0] 02:51:16
                      Local via ge-1/3/9.100
39.39.39.0/24      *[Direct/0] 00:53:40
                    > via lt-0/0/10.100
39.39.39.2/32      *[Local/0] 00:53:40
                      Local via lt-0/0/10.100
40.40.40.1/32      *[Direct/0] 3d 00:16:48
                    > via lo0.100
41.41.41.0/24      *[Static/5] 00:53:40
                    > to 39.39.39.1 via lt-0/0/10.100
150.150.150.0/24   *[Static/5] 00:49:18
                    > to 39.39.39.1 via lt-0/0/10.100
                                        
SERVER.inet.0: 7 destinations, 7 routes (7 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

25.25.25.0/24      *[Static/5] 00:49:18
                    > to 39.39.39.2 via lt-0/0/10.200
39.39.39.0/24      *[Direct/0] 00:53:40
                    > via lt-0/0/10.200
39.39.39.1/32      *[Local/0] 00:53:40
                      Local via lt-0/0/10.200
40.40.40.0/24      *[Static/5] 00:53:40
                    > to 39.39.39.2 via lt-0/0/10.200
41.41.41.1/32      *[Direct/0] 3d 00:16:48
                    > via lo0.200
150.150.150.0/24   *[Direct/0] 02:50:24
                    > via ge-1/0/0.0
150.150.150.1/32   *[Local/0] 02:50:24
                      Local via ge-1/0/0.0

[edit]
lab@MX80-user# show forwarding-options helpers bootp 
relay-agent-option;
interface {
    ge-1/3/9.100 {
        server 150.150.150.2 routing-instance CLIENT;
    }
}