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MX 480 randomly dropping traffic.

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  • 1.  MX 480 randomly dropping traffic.

    Posted 07-06-2016 00:37
    Hi Team,

    One of our routers MX 480 has been misbehaving for the past two days... it just drops connections and clients connected to the router can't even ping their GW IPs which are defined on the MX itself, if I try ping the client IPs from the router also, I can't... then after some minutes it just starts working and all traffic flows well... also I have one upstream eBGP session that keeps flapping since the router started this behavior... if I check memory and CPU resource usage, it looks fine.. log messages (default syslog entries) arent showing anything strange, except this "l2adl- Mac move detected in the system" , I have since disabled the vpls instance where this MAC was learnt from and it's no longer showing up in the LOG now.
    Is there some sort of troubleshooting check list or basic things to look at in this particular scenario??

    The router keeps going offline from the NMS system and reappears again.

    I will appreciate ideas

    Thank you.

  • 2.  RE: MX 480 randomly dropping traffic.
    Best Answer

    Posted 07-06-2016 01:12



    One thing that comes to mind is ddos-protection.

    Could you check:

    show ddos-protection protocols [icmp | bgp]
    show ddos-protection protocols statistics terse
    show ddos-protection statistics

    Just in case you see any violation or dropped packets.

    May be looking at the logs as well for bgp teardown reasons or ddos.




  • 3.  RE: MX 480 randomly dropping traffic.

    Posted 06-19-2017 03:01

    Although Late, but this problem was caused by L2-loop in one of our ERP rings. this has also occured second time to one of other routers and we had to deploy VPLS loop prevention as the ERP terminates on VPLS instance on the MXs. 


    one helpful command was "show l2-learning mac-move-buffer". this shows the looping vlan and the instance it belongs.


    when this loop happens the symptoms are  many "ddos protocal violation" log messages. 


    one of the issues we were facing was eBGP sesions were flapping. 



    LOOPS are Bad!