Toshiba Phone System

Question for Cisco Professionals...is it safe to turn off CDP?

I have a medium small sized network...about 12 nodes each with a router and switch or stack. Cisco CallManager is the main VOIP with several servers (publisher and subscribers). My question is more about network security, safety and Cisco CallManager...I'm not entirely up to speed on the interactions on the network with CallManager between the servers and the phones. I know that without a VOIP system in-place, it's advised to turn off CDP unless you really need it, for security reasons. If I turn off CDP, will it affect anything in the VOIP system?

Public Comments

1. Yes, it will have an impact, particularly if you run PoE to those phones. Personally, I do not buy into the CDP security issue on the INTERNAL network - almost all of that information can be gleaned just as easily in other ways. The EXTERNAL network should have it turned off regardless. Hope this helps.
2. Cisco Phones talk with the Switch they are connected to by using CDP (for some administrative functions). Turning off CDP could have the affect of trashing your QoS VoIP settings. Do not do this unless you are sure you do not need CDP. Look for this command: mls qos trust device cisco-phone if you see it, the port needs to use CDP to detect the phone and trust the port