The dangers of nonpassive router interfaces

Been a little busy with interviews and getting set for two of my last four
classes (Graduate Accounting and Strategic Management). Meanwhile just
read a cool article by Stretch at Packetlife. Give it a read:

The dangers of nonpassive router interfaces

By default, any network interface advertised by an IGP is considered active for that protocol. This means that the router will send information out that interface in an attempt to advertise routes or form adjacencies with neighboring routers. While this provides a bit of convenience to the administrator, it also presents a gaping security hole if neighbor adjacencies are not securely authenticated...

Article on Mask comparison: subnet versus wildcard from Packetlife.net

Nice, quick and clean explanation/"new"reminder of subnet versus wildcard masks.

Quoted from Packetlife.net
Many newbie network admins express difficulty with the subnet-versus-wildcard masking paradigm. It is a commonly held belief that a wildcard mask is simply the inverse of a subnet mask, and this is often the case, but not necessarily. Here's a brief rundown explaining the purpose of both mask types. Click here for the rest!