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i have this case:on firewall 1 and firewall 2 configure routing ospf and vrrp in the same time traffic go to internet through firewall 1, from firewall 1 routing to internet through router 1 and router 2. If on router 1 Fiber optic cable is broken, so how to firewall known and just routing to router 2 ?enter image description here

  • If a link breaks on R1, it will trigger an OSPF update that will inform your firewall. If the link that breaks is between R1 and the firewall without any redundancy (which is not the case in your drawing), then the firewall will know it because he won't receive hello packet from R1. – Nakrule Jul 3 '19 at 13:24
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can provide and accept your own answer. – Ron Maupin Dec 15 '19 at 4:32

I assume you're asking if the Internet link on R1 is down, how will the firewalls know?

R1 and R2 will learn a default route from the ISP. If the link to R1 breaks, R1 will stop advertising a default route to the firewalls.

If R1 or R2 do not receive routes from the ISP, then they need to advertise a default route if the ISP is reachable. For a Cisco router, you can configure IP SLA to test the reachability.

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  • i use to huawei firewall usg6350 and on firewall i was configuare ospf, i want to ask could i use IP SLA ? thanks a lot ! – AndyDuoc Jul 8 '19 at 14:45
  • You would use IP SLA on the routers. But I don’t know if Huawei has similar features. – Ron Trunk Jul 8 '19 at 15:18

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