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disable cdp and lost telnet functionality

Hi, i would like to ask if it's normal to lose the telnet function on a cisco 2611 router when i disable the cdp (used no cdp run). The router is functioning ok but i could not perform any telnet, is this normal?


Re: disable cdp and lost telnet functionality


From my personal i have never faced with such an instance of getting disconnected after disabling CDP.

Do revert whether you are trying to telnet from the switch or from a wkstation ?

if yes from switch are you able to ping up the router ip ?

also from the wkstation is ur ip conenctivity on there ?


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Re: disable cdp and lost telnet functionality


It is not normal to lose telnet functionality when you disable CDP. CDP is a layer 2 protocol which carries some information about layer 3. Telnet is a layer 3 and layer 4 protocol. I am having trouble understanding how a change in CDP could impact telnet, unless your router is using On Demand Routing. ODR does use information from CDP to build the routing table.

I wonder if there might have been some other change made on the router which would explain this. Perhaps you can enable CDP again, verify that you have telnet capability, disable CDP again, verify whether you have telnet capability or not.

It would also be helpful if you would provide some additional information, including how both routers are configured, the exact command that you are using to initiate telnet, and the output of show ip route from the router.



Community Member

Re: disable cdp and lost telnet functionality

Hi Rick,

This is what is used:

configure terminal

no cdp enable

Then i entered activate the cdp again:

configure terminal

cdp run

and the telnet works again, just now, i tried a different approach. I went to the interface on the router that is connected to a switch. From the router interface i went to e0/0 and type no cdp enable

i was able to telnet now and the switch could now not see the router via cdp.

Thanks for your explanation its now clearer to me on which layer both works.

Thanks again,


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