cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
395
Views
20
Helpful
8
Replies

Catalyst 2000

Hi team

I have tried sh mac address-table but it is showing more than 24 mac's addresses is there any other command to see only 24 mac addresses (switch is having 24 ports only). 

1 Accepted Solution

Accepted Solutions

MHM Cisco World
VIP Mentor VIP Mentor
VIP Mentor

there is many MAC address 
1- MAC address of host connect to SW port 
2- MAC address of VLAN 
3- MAC of other SW if this SW connect via trunk to other SW

so sure the number not be exactly 24 it can be more. 

View solution in original post

8 Replies 8

MHM Cisco World
VIP Mentor VIP Mentor
VIP Mentor

there is many MAC address 
1- MAC address of host connect to SW port 
2- MAC address of VLAN 
3- MAC of other SW if this SW connect via trunk to other SW

so sure the number not be exactly 24 it can be more. 

Hi mhm cisco World,

I agree with you, if two switches connected via trunk link and hosts in that two switches are in same vlan and now we give the command (sh mac -add table vlan 3) then it will shows all pc 's mac addresses ? . I think so i have not tried yet I will try and let me know you. (Means we don't need to log on two switches) 

 

Yes, why MAC of host connect to other SW appear in trunk ?
simple if HostA ask arp for HostB and both in same VLAN then the SW will flood ARP to all port include trunk connect two SW, and that why your SW show host connect to other SW learn through trunk port. 
it normal. 

Ok, finally what I understood is  in production network we can able to see all pc's mac address with same vlan in single switch with one command. Thaqq

You are so so welcome, 

Hi mhm cisco World, 

How to enable the GUI mode for catalyst cisco 2960 switch. Pls share me if any commands available 

 

Hi

I must kick in here, because this is not correct. Imagine 2 switches swA and swB connected to each other. On swA there is pc1 and pc2 connected. Pc1 want to talk to pc2, it then sends an arp request to find out the mac of pc2. This arp is a broadcast, so it is flooded out all ports on swA it reaches swB who also floods to all ports (not the incoming port), and also swB updates it's mac address table, so it now knows pc1 is reachable from the port to swA. Now, if pc1 and pc2 is sending packets to each other, this conversation is only between the 2 ports on swB. No traffic for this conversation is seen on swB, so after 5 minutes swB flushes the mac entry for pcA in it's mac address table. So now you can't see pc1 mac address anymore in swB.

/Mikael

balaji.bandi
VIP Community Legend VIP Community Legend
VIP Community Legend

More than 24, how many you see in total.

1. 24 ports does not mean it should learn only 24 MAC address here.

2. if the Phone and PC connected for 24 ports, then it will be 48 MAC or more (some system MAC address)

3. if you have any PC have virtual running, then you see more MAC address from that device (depends on end port configuration)

4. if the switch Layer 3 vlan configured, it is acting as gateway you see more arp tables.

what model of Cat 2K switch ?

BB

***** Rate All Helpful Responses *****

How to Ask The Cisco Community for Help

Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community:

Recognize Your Peers