Changing the configuration of a VPN can have interesting side effects. In my case I had to open up the host permissions for my MySQL users and databases from a /24 to a /16 network. Should be easy… and it actually is. Here are the SQL commands you have to execute to perform such an update:
update mysql.user set host = '10.42.%' where host = '10.42.42.%;
update mysql.db set host = '10.42.%' where host = '10.42.42.%;
You can of course go crazy in the where clause and in- or exclude everything you want.