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Redundancy on WAN link


I have two WAN routers where two different ISP were terminating on the router and both the routers were connected to the Firewall through unmanageable switch as a mediator.

Also, I have two IANA subnet (ex. &, where is configured on Router A & is configured on Router B. On firewall interface1 IP is & interface2 IP is

Issue here is, Since, all both subet are directly connected from firewall to router, where ISP A goes down, only IP subnet on is going through ISP B. but, what i required is when ISP A goes down, i need all my traffic need to routed to secondary ISP link including subnet traffic.

Required your suggestion....

Everyone's tags (2)

Redundancy on WAN link

Hello, Manoj.

To keep both prefixes in case when singl router goes down, you need to run BGP with your ISPs and advertise your prefixes to both of them.

PS: having single firewall servicing single link is not a best practise; it' much better to run 2 firewalls in failover mode (having multiple contexts).

Community Member

Redundancy on WAN link

Thanks for your reply....

But if i run BGP also,it wont be effective.. becoz.. We have 2 default gateway ( & pointing to two different routers... So, if we ru n BGP also, If primary link goes down (, incoming traffic will come via secondary link( but outgoing traffic will fall on primary link( any suggestions...

VIP Purple

Re: Redundancy on WAN link


Below is a just a default scenario but you could also incorporate this with PBR

Ip sla 1
Echo-Icmp (dest isp1) (scr wan link to isp1)
freq 5
ip sla schedule 1 start-time now life forever

track 1 rtr 1 reachability
Ip route x.x.x.x x.x.x.x ISP1 200 track 1
Ip route x.x.x.x x.x.x.x ISP2 200


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