14.1. Introduction to Layer 2 Security

If you think about how networking equipment is configured when you buy it nowadays, you can very clearly see that far lower security settings are configured by default on equipment that is used inside your enterprise. External protection devices, such as firewalls, come almost completely secured. Only traffic that you specifically authorize and configure is allowed. Granted, for a long time, the primary thoughts about routers and switches has been that they are for internal communication, and provide an efficient (or fast as possible) delivery to enterprise traffic. With almost no security configuration, those devices are open targets for attack. Unfortunately, a Layer 2 network that is compromised can ...

Get Cisco® Network Professional's: Advanced Internetworking Guide now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.