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Is it possible do packet capture on MX104 without use analyzer?

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  • 1.  Is it possible do packet capture on MX104 without use analyzer?

    Posted 11-30-2020 04:01
    Hi all,


    Below is my topology:

    FW ---> L2-Switch ---> (ge-0/0/0) MX104 (ge-0/0/1) ----> L2-Switch  ---> Upstream.


    Based on topology above is it possible to do packet capture on MX104 without using analyzer. I want to capture traffic in/out on ge-0/0/0 & ge-0/0/1 with specific source and destination ip address. Especially want to capture related to  MTU mismatch issue.


    [MX] Example: Configuring port mirroring on MX devices - Juniper Networks
    Juniper remove preview
    [MX] Example: Configuring port mirroring on MX devices - Juniper Networks
    This article explains how to configure port mirroring on MX devices with the help of an example. For basic port configuration steps, refer also to Configuring Port Mirroring on M, T MX, and PTX Series Routers. Topology In the above setup, SSH traffic is being sent from ixia port 10/11 to ixia port 10/12.
    View this on Juniper >


    Thanks and appreciate any feedback


  • 2.  RE: Is it possible do packet capture on MX104 without use analyzer?
    Best Answer

    Posted 12-01-2020 08:46
    Unfortunately, no, since it sounds like what you're trying to capture is considered transit traffic.  In case you aren't aware, Juniper splits traffic into two categories, transit and exception.

    • Exception traffic is traffic that is sourced or destined to addresses on the device itself (i.e. interface addresses).  The typical examples of this are routing protocols or ICMP. This type of traffic can be captured via the "monitor traffic" command.
    • Transit traffic is traffic that goes through a device (i.e. ingresses an interface and egresses another).  This type of traffic cannot be captured without using port mirroring.


    ------------------------------
    Jordan Head
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    JNCIE-SP 2728 | JNCIE-DC 271
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  • 3.  RE: Is it possible do packet capture on MX104 without use analyzer?

    Posted 12-01-2020 09:01
    Hi Jordan,


    Noted. Thanks for your feedback