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Order of operation MX5

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  • 1.  Order of operation MX5

    Posted 07-07-2017 14:10

    Hi everybody,

     

    Please consier the following :

    Below our router is configurde to use NAT for certain traffic, filter based forwarding for some other traffic.

     

    ------------f1 MX5-f2-----Egress traffic ( natted)

     

    Focusing on the traffic entering F1:

     

    1)When dealing with MX5, what is the order of operation between NAT policy and filter based forwarding i.e which one is checked first?

     

    Focusing on the Traffic entering F2

     

    2)When dealing with MX5, what is the order of operation between NAT policy anf filter based forwarding i.e which one is checked first? ( for example  in Cisco NAT table is checked first to determine if the traffic is return traffic previosuly natted before any Policy based routing is checked)

     

    3) Does SRX follow the same order with regard to NAT and Filter based forwarding ( Cisco's equivalent of Policy based routing ?

     

    Thanks and have a nice weeekend!!

     

     

     

     



  • 2.  RE: Order of operation MX5
    Best Answer

    Posted 07-08-2017 23:07

    Hi,

     

    Input firewall filters are processed before destination NAT and destination NAT is executed before forwarding lookup.
     We can disregard source NAT because is happens after the forwarding lookup and therefore has no impact on anything we investigate now.

    Please refer the below two link for details:

    http://www.juniper.net/documentation/images/g034201.gif

    https://www.inetzero.com/fbf-nat/




    Regards,
    Rahul

    Please mark my solution as accepted if it helped.