[GRLUG] Capturing mirrored traffic from a trunk port

Adam Tauno Williams awilliam at whitemice.org
Tue Jul 20 16:52:24 EDT 2010

I have a Cisco 2960GTC switch where port X is a trunk port (multiple
vLANs run between this port and subinterfaces on a Cisco 7200).  However
when I capture this traffic to port Y -

(config)#monitor session 1 source interface Gi0/X both
(config)#monitor session 1 destination interface Gi0/Y

- I believe I see all the traffic, but packets do not appear to have
vLAN 802.1q tags.  I'm capturing the traffic with Wireshark v1.2.1

I've tried setting Gi0/Y to switchport trunk mode, to no effect.

Do I need to do something on the switch or is it possible the ethernet
interface on the Linux workstation is stripping the tags?
Adam Tauno Williams <awilliam at whitemice.org> LPIC-1, Novell CLA
OpenGroupware, Cyrus IMAPd, Postfix, OpenLDAP, Samba

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 198 bytes
Desc: This is a digitally signed message part
URL: <http://shinobu.grlug.org/pipermail/grlug/attachments/20100720/8cf02ca4/attachment-0001.pgp>

More information about the grlug mailing list