Tutorials · Routing & Internet
How to Set Up Dual-WAN Failover With a 4G LTE Backup
Keep a branch online when the fibre fails: add a 4G LTE link as a backup WAN with health checks and automatic failover.
Before you start
- A gateway with two WAN ports or a WAN + LTE option
- A 4G LTE router or CPE with an active SIM
Step by step
Connect the LTE router
Place it where signal is strongest and connect it to the gateway's second WAN port. Put the LTE router in bridge or router mode with a fixed LAN IP.
Configure WAN2
Set WAN2 as DHCP or static to match the LTE router, and give it a lower priority (higher metric) than WAN1.
Add health checks
Make the gateway ping two reliable Internet hosts through WAN1 every few seconds and declare it down after several failures.
Enable failover
When WAN1 fails, the default route moves to WAN2, and moves back when WAN1 recovers.
Limit backup usage
Optionally block heavy traffic (updates, video streaming) on the backup to control mobile data costs.
Test
Unplug WAN1 and confirm that payments, VPN and voice keep working.
Pro tips
- Choose the mobile operator with the best coverage at the site.
- Monitor data usage on the SIM.
FAQ
Frequently asked questions
Will VPN tunnels survive failover?
They reconnect over the backup link if the remote side accepts the new IP, or use dynamic DNS and dead-peer detection.
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Ask Navijin technical support or an authorised partner for help with your configuration.