Redundant interface configuration in cisco router

Question:

I have a scenario WS-C3750V2-48PS-S like this.

Two firewalls are connected in Active-standby mode and tracking the inside and outside interfaces. There is a connectivity from router to the primary firewall portX and router is used for reaching the backoffice locations.Here my problem is whenever the firewall failover happens i lost connectivity to the backoffice networks from my inside network of firewall. So is ther anyway to configure the Cisco router with redundant interface like if the interface (connected to primary firewall) goes down, traffic should automatically pass through some other port and it should be connected to standby firewall portX.

Answer:

Cisco routers support "backup interface" feature

Backup interface remains down when primary is up. When primary goes down, backup interface comes up

You need to configure the backup interface command under primary  interface

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