Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

So I have this Cisco switch (Cisco SD2005) and I need to turn off the (probably) CDP:

14:58:53.235097 01:80:c2:00:00:01 (oui Unknown) > Broadcast, ethertype Unknown (0x8874), length 60:
    0x0000:  e008 8f4f d8c2 fa05 da4e 5010 0000 0000  ...O.....NP.....
    0x0010:  0000 0000 0000 0000 0000 0000 0000 0000  ................
    0x0020:  0000 0000 0000 0000 0000 0000 0000       .............. 

How can I do this?

I'm not familiar with Cicso switches so I need a little description for it.

AFAIK this is how can I turn CDP off (got this from my friend):

switch# enable
switch# configure terminal
switch# no cdp run
switch# show cdp neighbors

 % CDP is not enabled           

!--- This message indicates that CDP is disabled on this device.

swithch# end

But this switch is an "unmanaged" switch (?)

p.s.: is the tcpdumped data CDP at all??

share|improve this question
The frame you captured is not CDP but STP (the source mac is from a "reserved" block). – petrus May 2 '12 at 8:56
You will get more useful answers if you explain your actual problem. This is a "It's very important that I get the demons out of my grandmother's head. What should I do?" kind of question. (There's may or may not be a real problem, but whatever it is, the way you've explained it won't get you a useful answer.) – David Schwartz May 2 '12 at 9:24
up vote 2 down vote accepted

That's not CDP. It is some kind of broadcom loop detection traffic. See:

My guess is that it from a client connected to the switch, not from the switch itself.

share|improve this answer
No, hosts don't care about L2 loops. But it's indeed a broadcom loop detection frame. – petrus May 2 '12 at 12:20

Firstly, why do you think you need to disable CDP?

Secondly, I don't think that switch even has CDP.

Finally, if it's unmanaged then you're out of luck anyway. The whole thing with unmanaged switches is that there is no configuration to edit. It's a plug and play device, and you get what you get.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.