Time
13 hours 57 minutes
Difficulty
Beginner
CEU/CPE
14

Video Transcription

00:00
Hello and welcome back to I C. Ndy one interconnecting Cisco networking devices. Part one
00:05
this is episode 333 Analyzing where it's Ethernet switches, son frames.
00:11
I am friend Arun. I'll be your instructor for this course in the last video, one over some basic troubleshooting commands and methodologies for miss configured switches.
00:19
This episode of recovering how to think like a switch in where they're gonna send the frames and where the
00:25
should be. Sending the frames,
00:28
learning objectives were gonna think back and think about the 14 path of switch uses.
00:33
Good pre assessment here. What does the switch use for forging frames? Give me a few seconds.
00:41
All right, Hopefully you got the mac address table
00:45
Are so pass of the frame here. The biggest thing you don't want to use. The first command here is the show Mac address table dynamic.
00:52
This is gonna tell you if the Mac address is on the run port or, um
00:57
X's
00:59
right. Just think back to the original
01:00
lesson that house switches forward. Friends that use that Mac users table
01:06
s use of messages. So kind of the steps that's gonna dio is gonna receive that frame on the incoming interface is going to say, Is this a trunk or access port? Do I have a port security violation? You know
01:19
things of that nature. And from there, if it's an access port, it's gonna say Cool. I just got a frame on F A 02
01:26
for on the line and 10. This is unauthorized. Airport security is not enabled.
01:32
So I'm gonna go ahead and take a look at the destination address or Mac address
01:36
on the Mac address table. If I have that Mac address in there,
01:41
I'm gonna go ahead and just send that frame out. That one port.
01:46
So for the destination, if it doesn't know where it's at,
01:49
is he gonna say, Okay, send it out. All ports, except for the one that came in on.
01:53
And if it's also, if it's, ah, broadcast frame instead of a unique *** for being a one for one
01:59
broadcast being want all it's just gonna flood that frame. So it goes out. All friends, except for all ports, except for the one who came in up.
02:07
So quick. Demonstration Here. We got Bob with it up with a B B. A suit with A a B, B, B B
02:15
and the Sun mail server with a B B C. C.
02:20
So I think What? Bob, over here.
02:22
You think
02:23
he's gonna send a frame, too?
02:27
But I was gonna send a frame down to sue. Couldn't come in here. Say, is this an access board or a trunk port?
02:32
Do I have port Security enabled? No. Okay, so I received a frame on F A zero to We're all in the line. 10.
02:42
So it says Okay, so I do have a spot in my Mac address. Deal over Sue. So I'm gonna go ahead. Just send that out the trunk port for F A 0 24
02:50
and where it's gonna add that v land tag. Since the villian 10 is not native V lane on these switches,
02:58
right,
02:59
So it's going to send it down to here. Switch to is going to receive that frame.
03:02
So you think Is this an access port or trunk port? This is a trunk port. It has a V Lyon tag. So it's gonna go ahead and say, OK, this is Mentor v. Lyon to on Mac address A a B B B B B
03:15
and it's gonna strip that veal and tag off and send it out. That known interface F A 06 for Sue.
03:23
How it runs, remember, is gonna go in,
03:28
determine where it needs to go. If it needs to go out a trunk port or not
03:32
that it will send it out. It'll tag it with villain 10.
03:38
Remember the Eastern ETS header?
03:44
And then when it gets in here, it's gonna strip off that
03:46
header and just go back down to the Internet frame
03:50
down here.
03:53
Real simple, um, rolled down and dirty. So what we're gonna do, I'm gonna go ahead and just bring up the Mac address deal for one of my switches.
04:01
Okay, let's bring up buddy.
04:03
I just did a reload on it. So what's going on? Get logged in cyber? Very.
04:09
He and
04:12
Mr in a show. Mac, address table dynamic and see what we got.
04:16
All right, so we only had two. And 60 currently we are switch one.
04:23
So if we were to send a frame from, let's say if a zero to phaser six, it would immediately just come in and say, Okay, I gotta I gotta pour for that
04:30
I'm gonna send it out. You know, I fe 06
04:32
if we have a
04:34
If we go to send a brain too in our device has not recognized in the Magno stable is going to say OK, flood the frame all ports except for F A zero to the one that came in on
04:46
neighbor.
04:47
That's basically what you're gonna wanna look at.
04:50
Look, a trunk poor configuration. Look at whether it's in the Mac address table. It was not in the Mac address table. A quick way to push it into the Mac address table is to get on that device physically or logically, and, um, send a ping to someone on the network. It might fail.
05:10
Um,
05:11
but what is doing is pushing frames and pushing packets through that switch so it'll register. That's Mac address to the interface.
05:19
So when I go ahead and get back down putting,
05:23
we will move on to the post assessment. So it's going to throw back here. What is the default aging timer for the Mac address table?
05:30
See if you remember here,
05:35
all right. It is 300 seconds or five minutes
05:40
in the next episode, we're gonna look at trouble shooting port security.
05:44
And, as always, if you guys have questions, need some help. Feel free to shoot me. Message. Otherwise, thank you for watching this video before to see me the next one.

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