Feedback on Services — DNS Resolver
There is no info about "OpenVPN Clients" - 'Register connected OpenVPN clients in the DNS Resolver'
"If this option is set, then the common name (CN) of connected OpenVPN clients will be registered in the DNS Resolver, so that their name can be resolved. This only works for OpenVPN servers (Remote Access SSL/TLS or User Auth with Username as Common Name option) operating in "tun" mode. The domain in System: General Setup should also be set to the proper value."
see also #10999