I have a customer with a ipoffice rel 9.? They have a remote location that has 6 9608 phones. Their IT guy set up a VPN between the two. It's been working fine for over a year. Last week the remote phones started going down. The phones go up and down, sometimes they stay up for a couple hours sometimes just a few minutes. When they go down, they go through the boot up phase then get stuck on discovery. After a time they will connect. I'm thinking it's the firewall, any thought?