show mac address-table

[leoaraujo79]

Hi,

I am doing a lab using packet tracer and do not know how to find the right answers.

The lab show me a source mac address AAAA  and a destination mac address BBBB

Whitch interfaces will be use to send the fragments.

I use the show mac address-table and could find only mac address AAAA on the address-table, the mac address BBBB is not present.

Where should I look next?

[Antonio Knox]

What model switch and IOS verwsion are you working on?

[leoaraujo79]

2950 switch

not sure about the IOS version but maybe 12.5     packet tracer 5.3

[Alvaro Garcia · Accepted solution]

If the destination MAC address is not in the mac address table of the device then the frame would be broadcasted to all the ports part of the VLAN...

[leoaraujo79]

I have to select only 2 interfaces. Flood all ports isn't available.

[Alvaro Garcia · Accepted solution]

the packet would be forwarded to all the ports that belong to the VLAN where the packets was received from...

If the packet comes from VLAN 777 and the destination mac address is not stored on the mac table then the switch will flood the packet through all the ports that are part of VLAN777 except the port where the packet was received from.

Therefore, you should look what interfaces you have on the switch part of that VLAN and chose them...

[leoaraujo79]

Hi Alvaro,

Thanks for your help but on the lab I just had access to a switch CLI and there isn't vlan set.

I do understand the concept of what a switch do when a mac address isn't in the mac address table.

My problem is that the only command I know that check a list of mac address is

show mac address-table

the mac AAAA is on the list,  the switch know about it on F0/3 interface.

to answer the question I should find the mac BBBB relaited to a interface port but when I check on the mac address table it is not listed.

So if there isn't any where else to look for the mac BBBB I guess the lab has some kind of problem or who knows.

Thank you

Leandro

[Antonio Knox]

You could ping the ip address of BBBB, and he should appear in the mac-address-table.  There are plenty of ways to get him to come out to play.

[leoaraujo79]

I wish they displayed the ip address of host BBBB.

[Alvaro Garcia · Accepted solution]

What other information do you have about host AAA and BBB? IP addresses maybe? What is the topology?

[leoaraujo79]

I found the answer for my question.

mac AAAA was on the list and it was part of Vlan 77, on the list of interfaces I had available was the port it come from, and the trunk link from Vlan 77.

So I should had select the interface F0/3 as the source and the F0/12 witch was the trunk link of that switch.

Alvaro your answer was wright from the start.

I just did not realize that it the switch had one trunk link and 2 Vlan it would flood the frame on the vlan where the source was set.

Basically F0/2  - 10 made parte of vlan 77

F0/13 - 24 made parte of vlan 88

Trunk link for valn 77 only alow trafic form native vlan and 77 = F0/12

Trunk link for valn 88 only alow trafic form native vlan and 88 = F0/11

The only ports that could be select as answer was F0/3 - source and F/012 trunk link = flood