SPAN port issue 2960X

[d.allison]

I have multiple 2960x switches, all running Version 15.2(4)E3, RELEASE SOFTWARE (fc2)

All have the same config.  I am having an issue with one of the switches.  I have SPAN ports set up as per below:

monitor session 1 source interface Gi1/0/25
monitor session 1 destination interface Gi1/0/44

On the switch I am having the issue with, the device plugged in to the destination port is not accessible.  I cannot ping or connect via VNC.  I CAN ping and connect via VNC for all of the other switches.

If I remove "monitor session 1 destination interface Gi1/0/44", I am then able to ping the device (and connect via VNC).  The config on the port is empty.

If configure the port to mirror other (non-SPAN) ports, I can access the device connected.

I have tried different ports for the SPAN destination, and have replaced all Ethernet cables.

I am at a loss, considering all other switches (5 others have same config).

[Julio E. Moisa]

Hi

Your config is fine, If you are using span sessions and sending traffic to a destination port, this switchport must be configured as default, in few word no configuration under the port. 

Usually the recording systems or sniffers have 2 ports, one without any configuration and the other one for management that include IP settings.

If you are using a laptop, you could use you LAN port with not IP settings and use the WLAN port to manage it.

Hope it is useful

:-)

[d.allison]

Hi Julio,

Thanks for the response.  The destination switchport doesn't have any config.  The other locations with the same setup are not having the issue... I am able to ping the device (a DVR) connected to the switchport with the monitor statement entered.

On the problem switch, if I start a constant ping to the device (without the SPAN destination configured) I get responses.  As soon as I enter the SPAN destination, I start dropping all pings.  When I remove the SPAN destination, the pings are successful once again.

I am just confused because this behavior is isolated to one switch.

[Julio E. Moisa]

If Im not wrong when the span destination port is set up the port should be seen like disabled or other state, I dont remember right,

Can you execute show interface status or show ip int brief 

and see how the port looks?

[d.allison]

It shows as up and connected.  If I set the SPAN destination, it shows as monitoring.  Other switches show as monitoring on the destination port, but I am still able to ping the device.  Not so on this problem switch.

[Julio E. Moisa]

Yeap that is the correct state, the device connected to this destination port has 2 NICs? Could you please share the config of the destination port?

Thank you in advance.