Have a remote employee that VPN's to our server. Their home IP address changed and now they cannot VPN. We use whitelisting on our router, meaning no outside IP's get past the router unless the IP is listed. I added the employee's new IP to the router, but they still can't VPN.
Here's the weird thing, though. When he is trying to VPN, the router logs don't show he is even making it to the router. If he does "Telnet", his IP shows up in the log on the router, but if he tries to VPN from the same machine, nothing in the log on the router.
Another thing he tried was using his hotspot on his phone and when he tried to VPN his laptop using the phone's hotspot, that IP address for the phone hotspot showed up in the log on the router, but he wasn't able to VPN.
So, what do we need to check?