I’ve received several e-mails responding to the mismatched OSPF subnet challenge. Some of the readers claimed that the configuration would work as-is; if you were one of them, I would advise you to do some lab tests the next time.

A few of the respondents also noted that it was more a review question than a challenge (since I’ve been writing about this topic a few days back), and everyone who decided the configuration has to be fixed has provided the correct solution: you have to configure the Fast Ethernet as a point-to-point OSPF interface and the routers stop complaining about the OSPF subnet mask mismatch.