Configuring Static Null Routing

You add a static route to a Null 0 interface when an access server with many clients is in your network. This causes NetVisor OS to install host routes in the access server routing table. To ensure reach-ability to these clients, while not flooding the entire network with host routes, other routers in the network typically have a summary route pointing to the access server. In this type of configuration, the access server has the same summary route pointing to the access server Null 0 interface. If not, routing loops may occur when outside hosts attempt to reach IP addresses not currently assigned to a client but are part of the summary route. The access server bounces the packets back over the access server default route into the core network, and because the access server lacks a specific host route for the destination.

This feature introduces a new parameter for the command, vrouter-static-route-add:

CLI (network-admin@switch) > vrouter-static-route-add vrouter-name vr1 network gateway-ip ip-address 

drop       Drop packets matching this route

NetVisor OS designates the drop keyword as mutually exclusive with keywords such as gateway or interface. Either drop or gateway must be used for valid syntax. Static routes with gateways cannot co-exist with drop routes for the same prefix.

CLI (network-admin@switch) > vrouter-static-route-show


vrouter-name network         gateway-ip    bfd-dst-ip distance  drop

------------ --------------- ------------- ---------- --------  ----

vr1 ::             ::         1        yes  

vr1  ::         1        no   

vr1 ::             ::         1        yes  


CLI (network-admin@switch) > vrouter-routes-show format network, type, interface, next-hop, distance


vrouter-name network               type      interface next-hop      distance

------------ --------------------- --------- --------- ------------- --------

vr1       static     Null0                    1        

vr1       static     Null0                    1        

vr1       static     eth2.4092  1        

vr1      connected  eth2.4092                        

vr1          2018:192:168:100::/96 connected  eth2.4092                        

vr1          fe80::/64             connected  eth2.4092