Final answer:
The best practice for CDP and LLDP is to disable both on all interfaces where they are not necessary to prevent potential information disclosure and enhance network security.
Step-by-step explanation:
The best practice concerning discovery protocols such as CDP (Cisco Discovery Protocol) and LLDP (Link Layer Discovery Protocol) on network devices is to disable both protocols on all interfaces where they are not required. While CDP is proprietary to Cisco devices and LLDP is an open standard compatible with devices from multiple manufacturers, the main concern is security.
Discovery protocols can reveal information about the network topology and connected devices, which might be sensitive. Hence, it is a common security practice to disable these protocols especially on interfaces that connect to external networks or user-accessible ports to prevent information disclosure to unauthorized users.
It is not advisable to use the default router settings for CDP and LLDP as it may not align with the specific network requirements. Instead, it is recommended to configure the protocols based on the network design and needs.
The best practice is also to disable both protocols on all interfaces where they are not required. This reduces unnecessary network traffic and improves security by limiting potential information exposure.