Wireless Access

Reply
Contributor II

How to capture 802.1q packet in the trunk ports?

Hi guys,

 

I was trying to capture a 802.1q packet from a trunk port,but it wasn't successed.

 

My topology is PC---SW(aruba 1500)--controller(3600).

From PC to SW is access port which belongs to VLAN 10; from SW to controller is trunk port which allows all the vlans.

Also I set 2 SVIs in the SW,interface vlan 10 = 192.168.10.1/24, interface vlan 20 = 192.168.20.1/24.

The PC's IP address is 192.168.10.2/24,its gateway is 192.168.10.1.

In the controller,I set a SVI which is interface vlan 20,IP address is 192.168.20.2/24,

 

For now, I can easily ping 192.168.20.2(the IP address of controller) from PC side, but when I captured the ICMP packets from the trunk port, it only showed ethernet II protocol and IP protocol, and nothing between them.

 

The three ways I used to capture the packet:

1,Mirroring the trunk interface in controller.

2,Mirroring the trunk interface in SW.

3,Add a hub between the SW and controller.

 

Also I tried to change the setting of my NIC card,enable vlan tagging or disable it.

 

Please someone tell me, where am I wrong?

 

PS:I can capture the 802.1q packet from the GNS3 with the CIsco IOS.

 

Guru Elite

Re: How to capture 802.1q packet in the trunk ports?

Most laptops cannot see 802.1q headers. Best bet is to use the packet-capture command in the controller because it will encapsulate into GRE and preserve the headers.


Thanks,
Tim

Tim Cappalli | Aruba Security TME
@timcappalli | timcappalli.me | ACMX #367 / ACCX #480
Contributor II

Re: How to capture 802.1q packet in the trunk ports?

I can see the 802.1q header for GNS3,same laptop.

And I didn't use wireless,this is all wired.

Guru Elite

Re: How to capture 802.1q packet in the trunk ports?

For GNS3, are you capturing your physical NIC or a virtual interface?


Thanks,
Tim

Tim Cappalli | Aruba Security TME
@timcappalli | timcappalli.me | ACMX #367 / ACCX #480
Contributor II

Re: How to capture 802.1q packet in the trunk ports?

Yes,from the real NIC card,I can see the 802.1q tag.

 

You can see the ICMP traffic from 192.168.10.2 to 192.168.20.2.

Guru Elite

Re: How to capture 802.1q packet in the trunk ports?

I would still just use the packet-capture command.


Thanks,
Tim

Tim Cappalli | Aruba Security TME
@timcappalli | timcappalli.me | ACMX #367 / ACCX #480
Contributor II

Re: How to capture 802.1q packet in the trunk ports?

Could you please tell me more about this command?

 Then I can try it tomorrow,thanks.

Guru Elite

Re: How to capture 802.1q packet in the trunk ports?

Contributor II

Re: How to capture 802.1q packet in the trunk ports?

Is that port mirririong ?

If so, I have already tried.Both controller side and SW side.

Search Airheads
cancel
Showing results for 
Search instead for 
Did you mean: