User passwords for l2tp/ipsec

[Mr.Si]

Hi all,

I've been setting up l2tp with ipsec following the guidance in the documentation provided on the pfsense site, for my installation of 2.3

what I'm confused about is actually just the password characters allowed - it doesn't seem to let me use special characters such as ! or [

I'm migrating from a draytek 2850 with dial-in users set up, to leaving that as the modem element and using the pfsense box as the hw firewall.

Is there a list somewhere which shows which character sets are allowed in vpn user passwords?

Thanks