01-01-2012 10:37 PM - edited 03-07-2019 04:07 AM
Hi,
I have CISCO catalyst with VLANs (VLAN ID 33, 36, 40-53) configured. I need to configure port mirroring in Switch 3750 for NAC (Network Access Control). I need to Monitor all the VLANs. Here is the SPAN configuration of switch:
Interface fa 1/0/8
Description ******NAC-MONITOR-PORT******
Switchport trunk encapsulation dot1q
Switchport mode trunk
|
Interface fa 1/0/9
Description ******NAC-Response-PORT******
Switchport trunk encapsulation dot1q
Switchport mode trunk
Monitor session 1 source vlan 33 , 36 , 40 – 53
Monitor Session 1 destination interface fa 1/0/8 (here I am not able to set encapsulation dot1q ) because the error occurred saying %one or more dest port do not support the encapsulation%. please suggest why this error occured?
01-01-2012 10:50 PM
It looks like you need to change the destination command to:
monitor session 1 destination interface fa1/0/8 encapsulation replicate
Otherwise, it tries to send the traffic untagged. If you want everything that the interface is seeing, that won't work.
01-04-2012 03:39 AM
i Have changed the destination command as you have suggested:
monitor session 1 destination interface fa 1/0/8 encapsulation replicate
but still i am not able to see mirror traffic from VLAN 33, 36 , 40 -53 in NAC appliance. All the traffic is seen as untagged.
01-04-2012 12:21 PM
Have you tried hooking up a sniffer like Wireshark to capture a sample of the traffic you're seeing? I'm wondering if the 3750 is passing the traffic tagged and the NAC is not set up correctly.
The other thought I had: is one of those VLANs a native VLAN? You don't show it in your config above; I wasn't sure if you abbreviated the configuration or if that's the entire config for those ports. If you've got a native VLAN and if that native VLAN is carrying most of the traffic, you won't see tags for the majority of it.
01-02-2012 01:07 AM
I just happened to go through the link and it suggests different ways of implemention
http://www.colasoft.com/resources/span.pdf
Not sure although if it work.
-Vijay
02-27-2013 03:40 PM
Anyl,
was your original problem resolved? If so, can you share the solution?
Thanks,
David
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