I use option 121 as part of my work, though I am not an expert on DHCP. This attack does make sense to me and it would be hard to work around given the legitimate uses for that option.
Adding routes for other thing on the network the clients can reach directly and remove some load from the router. For example, reaching another office location through a tunnel, you can add a route to 10.2.0.0/16 via 10.1.0.4 and the clients will direct the traffic directly at the appropriate gateway.
Arguably one should design the network such that this is not necessary but it’s useful.
I use option 121 as part of my work, though I am not an expert on DHCP. This attack does make sense to me and it would be hard to work around given the legitimate uses for that option.
What are the legitimate uses of option 121?
Adding routes for other thing on the network the clients can reach directly and remove some load from the router. For example, reaching another office location through a tunnel, you can add a route to 10.2.0.0/16 via 10.1.0.4 and the clients will direct the traffic directly at the appropriate gateway.
Arguably one should design the network such that this is not necessary but it’s useful.