VPN which wan is using?

Hi,

I have a couple of routers connecting to headquarter router via VPN using an L2TP Client.
The router has two wans. A main and a backup wan.
How I can know which wan is using to connect to headquarter the L2TP Client?

Any advice will be welcome.

Thanks.

xavier

Unless you force something else, it’s gonna be the one with currently active default route.