For all VPN client configs, if domain is used, IP may expire

[markpash]

• Domain is resolved and IP is inserted into address book
• If IP behind domain changes, IP in address book is replaced
• Something is rechecking the domain and resolving the IP on an interval
• This causes the tunnel to die because the IP exception in the address book is not valid for the current tunnel
• then we end up with a flapping VPN client tunnel

We need to figure out a way to make this stable.