00:04
the next topic of discussion is a very sharp topic, and it deals with Cisco Discovery Protocol.
00:11
Cisco Discovery Protocol is a layer to protocol that is used to map out your network.
00:17
Now the words map out. Your network should set. Send warning bells in your head because insecure environments
00:25
you should not allow people to map out your network. So this protocol should be turned off
00:31
if you are in a secure environment, which
00:34
most of the time happens In the DC Washington metro area,
00:43
CDP works between devices.
00:46
It is Cisco proprietary and on by default.
00:50
So if I go on rather one
00:52
and CDP is on by default
00:55
and if I say execute the command
01:02
I see if physically you see look at art apology. You see a router two or one
01:11
is connected to a router. One
01:14
on router to one serial 0102 rather one serial 000
01:19
So if I go into outer one and execute the show CDP neighbor command or neighbors command,
01:26
I see the device i d of the device at the other end, which is rather one
01:32
my local interfere serial 010
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is connected to serial 000 off router one.
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So my router to one serial 010 is connected to serial 000 on router one.
01:51
The platform on Router one is a C 2800 series router.
01:56
If I execute the command Sure. CDP neighbor detail, neighbors detail.
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I see a little bit more detail about Router one.
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Router one is running version 12.4
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sub release 15 T operating system.
02:15
My interface serial 010
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The platform ISS see 2800 series router
02:30
and I also see rowdier ones I p. Address, which is 200. 202 100.1
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to show you that router ones I p address on serial 000 is actually 202 102 101.
02:45
I can go into Router One and execute the
02:50
you shou ID be inter fees,
02:53
brief command. And as you see, serial 000 on Router one. Has I p 201 11
03:00
now a variation of the show
03:05
CDP neighbors detail command because this one sure, you detailed information about all the devices you are connected to.
03:13
So if I execute this command on router one, it won't be as clean or if I execute this command. Yes, on router one.
03:23
Sure CDP neighbors detail.
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I see detail about switch one
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so router ones interface faceted at 00 is connected to switch ones. Fast. Ethan at Zito's Last 24
03:38
and the switch is a 35 60. Switch running
03:43
operating system version. $12 to sub release. 37 s e.
03:47
And I see information about rotter to a one, which is connected on the other side. On serial 000 router to one's address is 202 102 102
03:59
router ones into face 0000 is connected to
04:02
router to one's interface. Hero 010 and router to one is a C 2800.
04:11
See 2800 studies router
04:15
Now what if I just wanted to see you out? Or to a one? Variations of the shore CDB neighbor detail command is show CDP entry
04:27
are to a one are to a one being are two router to a one's host name
04:32
and hit enter. Then it would show me information Just about our to a one
04:38
and set off all my neighbors.
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Another variation of the shore CDP neighbor detail Command is sure CDP
04:48
show CDP Entry star which stands for Show all my entries once again similar to the show CDP Neighbor Detail command, you see switch one and router to a one, which is on the cereal and over our one
05:05
again. It showed me information about which one
05:12
Which one is connected to our one on fast Internet 00 locally and
05:18
fast. Lieutenant zero slash 24 on the switch in
05:21
and our two alone disconnected
05:28
on our one to our two ones as 010
05:32
Now, as I said, you should turn off CDP if you are in a secure environment so I could go to interferes. Fascinating that 00 and say no
05:46
enable. That turns off CDP on my fastest in at 00 interface which is connected to switch one. Now if I ask for
05:59
let's clear the CDP table for us
06:02
with this Claire CDB table command. Now, if I look at show cdp
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I don't see anything because CDP has not talked back and forth yet.
06:23
Let me bounce the interfaces.
06:27
Let me just reload this router real quick to hasten the process. I saved my work with the W R Command and reloaded the router.
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You would not do this at work. I'm just trying to hasten the process of the lab
06:44
show CDP neighbor detail
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That seems to have turned off CDP on all the interfaces.
06:57
Okay, we will go back a little bit.
07:00
No, we can keep rolling.
07:01
So as I said that in a secure environment, CDP should be turned off
07:14
go into an interface and say
07:16
no CDP unable to turn our CDP per interface.
07:21
Or you could say no CDP run
07:27
from config motew globally turnoff CDP on that device.
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Now, if execute the command show CDP neighbor,
07:39
I hear or I get a message saying CDP is not enabled.
07:44
This concludes our CDP lecture