Manually configuring a static route in router A would achieve the result: ip route 172.16.16.0 255.255.255.0 fa0/0
Why are we doing basic IP routing 101 on NANOG?
OK, since it's so basic why don't you explain how to have router A dynamically learn from router B that there is a new subnet on the local ethernet?
It cannot. IP works on layer 3. Ethernet is layer 2. Your local grouping happens on layer 2. Layer 3 does not know about it unless you TELL it about it.
So then what do you call a connected route (for an ethernet interface on a router)? If you use ethernet, at the edges of your network you HAVE to route IP blocks to the ethernet.
A connected route is installed only when you *CONFIGURE* it, something that you are refusing to do. Configure the connected route by assigning a secondary to the interface and your router will *know* that it can reach that subnet directly. If you do not want to do that, configure a dynamic routing protocol or insert a static route pointing to a router which knows how to reach that network directly. Alex