Internal vpn doesn't auto re-connect

Installing and Using OpenWrt Network and Wireless Configuration
1

Ciao!
How are you?
I have to be connected to my work, like this:

config interface 'sygnusvpn'
        option proto 'l2tp'
        option server 'vpn.hungary.hu'
        option username 'some-vpn'
        option password '1234567890'
        option ipv6 'auto'
        option metric '10'

The problem is that when the router IP changes, it is not auto re-connecting. How can I re-connect an interface?
With a scripts or a config?

Can I just add to the firewall with ifup some-vpn ? Or a config?
Thanks.

2

You need to somehow set this to on.

Infinitely resolve server