The wanmonitor package is an agent script that makes Multi-WAN configuration simple, easy to use and manageable. It comes complete with failover setup supporting many types of internet connections, including PPPoE and mobile connections. The uci configuration file /etc/config/wanmonitor is provided as part of the wanmonitor package.

The WanMonitor provides the following capabilities:

provides outbound WAN traffic failover connection setup
monitors primary link by checking interface status and repeated ping tests
automatically routes outbound traffic to secondary WAN interface if primary is down
automatically routes outbound traffic back to primary interface when it is available again
easy to use and manageable configuration via single file
up to 2 physical interfaces for easy failover setups

Configuration

All configuration is done in /etc/config/wanmonitor file. Options available:

check_host - IP address of remote host used to check Internet connectivity
flapping - Number of seconds to wait after switching WAN to reduce link flapping
interval - Number of seconds to wait between checks
sleep - number of seconds to wait for slow links during startup
wan_primary - Primary WAN interface name to use
wan_secondary - Secondary WAN interface name to use

What is more it can make a use of WAN routes metrics set in /etc/config/network, thus allowing to use PPPoE to work correctly. When PPPoE connection is established, it automatically adds a route with proper (higher) priority and this connection is being used as default. After a while, when WanMonitor notices primary connection is again available, it removes a route for secondary WAN connection (eg. in order to save mobile traffic).

Sample configuration

/etc/config/network: config interface 'wan1' option ifname 'eth0' option metric '0' option proto 'pppoe' option username 'login' option password 'password' option service 'PPPoE'

config interface 'wan2'
    option ifname 'eth1'
    option proto 'dhcp'
    option metric '5'
    option defaultroute '0'
    option service 'LTE'

/etc/config/wanmonitor: config wanmonitor option check_host '8.8.8.8' option flapping '60' option interval '5' option sleep '5' option wan_primary 'wan1' option wan_secondary 'wan2'