Chapter 11. Information Leaks with Cisco Ancillary Protocols

In a Cisco switched environment, there are many ancillary protocols: some proprietary, such as Cisco Discovery Protocol (CDP) and VLAN Trunking Protocol (VTP); some standard, such as Institute of Electrical and Electronic Engineers (IEEE) Link Layer Discovery Protocol (LLDP) and Link Aggregation Control Protocol (LACP). This chapter describes these protocols, sometimes not well known, and the associated risks, which are mainly information leaks, such as giving out information to a potential attacker.

Cisco Discovery Protocol

Cisco Discovery Protocol (CDP) is a Cisco proprietary protocol, which allows for layer-adjacent devices to discover each other. It requires little to no configuration. ...

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