When you configure OSPF network statements, IOS orders them most-specific to least-specific then does a top-to-bottom match of the interfaces. It doesn’t matter which order you put them in, the configuration will always be ordered with the longest prefix matches first. Lab time!
Here’s a story from last week with little of no teaching value. I got a call from one of our business units looking for some routing help. We don’t usually care about their production networks, but they were seeing some funky traceroutes, so I agreed to try and help them out.
A few hours ago, the last of the IPv4 addresses were allocated by IANA. Now’s the time to learn more about IPv6! Yesterday, I posted about EIGRP for IPv6, so I think I’ll continue the trend by introducing OSPFv3, which is the IPv6 implementation of OSPF
Feel free to correct all this stuff. Additions are also welcome. Study Questions How do I keep an area route from reaching a router in that area? You don’t. That defeats the whole purpose of having the topology database on…