CDP is a proprietary protocol designed by Cisco to help administrators collect information about both locally attached and remote devices. There are scenarios and cases where you would want to disable CDP. Some of these are described below:
CDP can be a security risk as it broadcasts information about your network devices like device ID, IP address, platform, capabilities, etc. An attacker with access to the network can use this information to understand the network topology and plan attacks.
Non-Cisco Devices: If your network includes non-Cisco devices, enabling CDP may not be beneficial as it is a proprietary protocol and may not be supported by other vendors.
Network Traffic: CDP messages are multicast every 60 seconds by default, which can consume unnecessary bandwidth and processing power on your network devices. In a large network with many Cisco devices, this could lead to significant network traffic.
Unnecessary in Static Networks: If your network topology is static and doesnât change often, there may be little benefit to having CDP enabled.
Public Facing Interfaces: It is not advisable to enable CDP on interfaces that are facing the internet or untrusted networks. This can expose your device details to potential attackers.
The typical rule of thumb is, if you donât need it, donât activate it.
A quick question. Is CDP considered Cisco proprietary or not? A lot of resources define it that way but just like Rene said before, some other platforms do support it, like Mikrotik
Great to hear from you again! Yes, CDP is proprietary, meaning it was developed by Cisco for Cisco, and it is not defined or managed by any standards organization like the IETF or the IEEE. An open standard on the other hand, is one that is managed by a standards organization like the ones I mentioned, and is openly available to be used by any vendor.
Now the question remains, how is a proprietary protocol like CDP supported by non-Cisco devices? Well, there are two ways this can be done. CDP is a relatively simple protocol with an unencrypted operation, so it can be analyzed and reverse-engineered easily, and some vendors have done this. Others may have been given explicit rights to use it in some memorandum of understanding, but nothing has really been published as far as I know.
Cisco hasnât acted against any vendors that have done this, as it is in their interest to have other vendors support their protocol. The use of multiple vendors is expected throughout a networkâs lifetime. Other vendors, including Ubiquiti, support CDP too.
So CDP is proprietary, in the sense that it is not managed by a standards organization, but it is not exclusively used by Cisco, as other vendors have adopted it as well, without any reaction from Cisco itself.
