The FIA customer has two internet connections from Service Provider . According to them, one connection works without issues, while the second consistently experiences problems. When they disable the primary connection and activate the secondary, they encounter Internet outages.

I’ve outlined a rough representation below.

FIA Customer Internal Network --- FIA CE Router --- DUT PE (Service Provider Router - Juniper Vendor) ---- Service Provider Core --- Internet

Service Provider router advertises a default route to the FIA customer. The FIA customer advertises their subnets XX.XX.224.0/24 and XX.XX.230.192/26 to Service Provider.

BGP session is stable and no session flapping observed. 

[email protected]> show route advertising-protocol bgp XX.XX.196.2

inet.0: 1083529 destinations, 2166656 routes (1083528 active, 0 holddown, 2 hidden)

 Prefix         Nexthop       MED   Lclpref  AS path

* 0.0.0.0/0        Self         150000       I

[email protected]> show route receive-protocol bgp XX.XXX.196.2

inet.0: 1083537 destinations, 2166672 routes (1083536 active, 0 holddown, 2 hidden)

 Prefix         Nexthop       MED   Lclpref  AS path

* XX.XX.224.0/24     XX.XXX.196.2              XXX96 ?

* XX.XX.230.192/26    XX.XXX.196.2              XXX96 ?

Since the customer reported outages when traffic is routed through DUT PE (Service Provider Router - Juniper Vendor), we applied a firewall filter on that router to verify incoming packets from FIA CE Router. The filter matched traffic from three different customer IPs, all destined for Google DNS. We observed that packets were only received from FIA CE Router, with no traffic from other devices. The below steps helped to narrow down that the issue was on FIA customer network. The steps outlined below helped us determine that the issue is within the FIA customer's network.

[email protected]# show | compare 

[edit interfaces xe-2/0/5 unit 1100 family inet filter]

+    input JTAC_FW;

[edit firewall family inet]

+   filter JTAC_FW {

+   interface-specific;

+     term 10 {

+       from {

+         source-address {

+           XX.XX.224.46/32;

+         }

+         destination-address {

+           8.8.8.8/32;

+         }

+       }

+       then {

+         count 46IP;

+         accept;

+       }

+     }

+     term 20 {

+       from {

+         source-address {

+           XX.XX.224.2/32;

+         }

+         destination-address {

+           8.8.8.8/32;

+         }

+       }

+       then {

+         count 2IP;

+         accept;

+       }

+     }

+     term 30 {

+       from {

+         source-address {

+           XX.XX.224.3/32;

+         }

+         destination-address {

+           8.8.8.8/32;

+         }

+       }

+       then {

+         count 3IP;

+         accept;

+       }

+     }

+     term 40 {

+       then accept;

+     }

+   }

[email protected]> show firewall filter JTAC_FW-xe-2/0/5.1100-i  

Filter: JTAC_FW-xe-2/0/5.1100-i                

Counters:

Name                        Bytes       Packets

2IP-xe-2/0/5.1100-i                  144          4         << When ping was initiated from FIA CE Router

3IP-xe-2/0/5.1100-i                   0          0

46IP-xe-2/0/5.1100-i                  0          0