Hi,

I’m currently managing a setup where we’re at our edge, we're punting packets 
to a routing-instance based on firewall matches in order to separate traffic 
between outside client traffic (which needs to be routed through the LB on 
return) and other internet-facing outbound. We have rib-groups configured for 
our routing-instances to import the direct and local routes, like the below 
(simplified) config example:

routing-options {
    interface-routes {
        rib-group {
            inet fbf-groups;
        }
    }
    ...
    rib-groups {
        fbf-groups {
            import-rib [ inet.0 lb1.inet.0 ]
        }
    }
}
...
firewall {
    family inet {
        filter BOUNCE_TO_LB
            from { 
                protocol tcp;
                source-port [ 80 443 ];
            }
            then {
                routing-instance lb1;
            }
        }
    }
}
...
routing-instances {
    lb1 {
        instance-type forwarding;
        routing-options {
            static {
                route 0.0.0.0/0 next-hop 1.2.3.4;
            }
        }
    }
}

The "lb1" routing-instance is simply a default route to the LB's gateway IP 
which is a directly connected interface to the router.

(This design is documented here: 
https://www.juniper.net/documentation/en_US/junos12.3/topics/example/logical-systems-filter-based-forwarding.html)

The problem I'm having is that because this setup imports all direct and local 
routes into the routing instance, packets that are punted to the routing 
instance that are destined for other directly connected hosts bypass the 
default route and get forwarded directly to the end host. For example, if I 
have a host hanging off of interface xe-2/0/0 with address 2.2.3.4/24, and I 
look in the routing-instance's table, I see:

edge-rtr> show route table lb1.inet.0   

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

0.0.0.0/0          *[Static/5] 37w1d 15:53:29
                    > to 1.2.3.4 via xe-1/0/0
2.2.3.4/24         *[Direct/0] 11w3d 10:42:47
                    > via xe-2/0/0.0
2.2.3.1/32         *[Local/0] 11w3d 10:42:47
                      Local via xe-2/0/0.0

So a packet with dest IP 2.2.3.4 goes directly to the host instead of going to 
the LB, which means it has the real host IP and not the VIP's IP as its source, 
which means no worky worky.

So the question I have is this - is there a way to filter the direct and local 
routes that are imported into a routing instance? In this case, I'd only want 
the direct route for the subnet containing 1.2.3.4, and no other direct routes.

Alternatively, would it be possible to *not* import any direct routes into the 
routing-instance (i.e. deleting the rib-groups syntax altogether) and instead 
add the direct and/or local route manually to the routing instance, so I can 
ensure that only the direct routes I need to resolve the next hop make it into 
the routing instance?

TIA,

-Chris





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