Situatie
1. Disable CDP on Exposed Ports
It’s essential to use CDP only where it’s needed. Disable CDP on interfaces connected to untrusted networks or devices, such as guest networks or employee devices, to minimize the risk of sensitive network information being exposed.
- Per interface:
no cdp enable - Globally:
no cdp run
2. Limit CDP Usage in Sensitive Areas
Enable CDP only where absolutely necessary, such as between core switches in the data center. Avoid enabling it on ports that connect the internal network to untrusted or external networks to prevent the exposure of sensitive details.
3. Implement Network Access Control (NAC)
Network Access Control (NAC) helps to authenticate and authorize devices connecting to the network, ensuring that only approved devices have access. This reduces the risk of unauthorized devices using CDP to gather information on the network’s structure.
4. Configure VLANs and Segment the Network
Segment your network using VLANs to limit interaction between different network segments. Separating production networks from employee or guest areas reduces CDP exposure to unauthorized devices and minimizes attack surfaces.
5. Monitor CDP Traffic for Suspicious Activity
Network traffic monitoring is essential for spotting suspicious activities. Use monitoring solutions to detect abnormal CDP messages or unknown devices sending such packets. Unusual CDP activity may indicate an intruder mapping out the network.
6. Consider LLDP if Working with Non-Cisco Equipment
If your network includes non-Cisco devices, consider using the Link Layer Discovery Protocol (LLDP), an open-standard protocol similar to CDP. LLDP allows for more granular control over shared information, reducing the risk of unnecessary data exposure.
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