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On Cisco routers there is an option to do port mirroring only on Rx or Tx side, by using this command:

monitor session session_number source interface interface-id [, | -] [both | rx | tx]

(Optional) Specify the direction of traffic to monitor. If you do not specify a traffic direction, the source interface sends both sent and received traffic.

  • both - Monitor both received and sent traffic

  • rx - Monitor received traffic

  • tx - Monitor sent traffic.

Is there a similar configuration on a Juniper MX960?

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Its possible.

In case link below breaks sometime in future.

Browse to Configuring Layer 2 Port Mirroring at MX Series Config Guide on Juniper Documentation Page.

Follow this Config Guide.

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Please can you give more details about what is found at the other end of the link, in case it stops working in future. – dunxd Oct 5 '12 at 23:21

The MX may have different limitations, but on EX series switches I follow this:

You can choose ingress and egress separately to monitor.

This may help too:

And this one looks most promising:

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Thanks For the answer, from the links I didn't actually saw the option to configure Tx / Rx mirroring seperatly in the MX960 if you understood this differently can you please point me to the configuration you saw, Thanks again for the support – Nir May 16 '12 at 13:02
just notice the following int he last link filter { output egress-portmirror; is that what you meant ? – Nir May 16 '12 at 13:07
well the output filter in that case goes to the analyzer ports.... on the other end though, you would have a filter for ingress, and for egress, or just one. – SpacemanSpiff May 16 '12 at 13:16

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