You may find the ISP does not provide a Public Static IP Address with a Business Account or any account type. An example of this would be Clear Wireless Internet. This issue can be surmounted by utilizing the DynDNS capabilities that exist within the modem and/or firewall you are using. It may be preferable to upgrade the ISP modem to their currently supported model. In the example of Clear Wireless Internet, this would be the Gemtek Clear Hub Express.
ISP Modem Bridge Mode
If the ISP modem does not have the capability of going into Bridge Mode, it may have the capability of utilizing IP Passthrough. You would then enable IP Passthrough and disable the ISP Modem firewall as the subsequent firewall appliance for the VPN will block inbound internet traffic. Or you could define port-forwards within the ISP modem rather than disabling the ISP modem firewall.
In the Clear Wireless Gemtek Clear Hub Express:
- Select Advanced Settings – Router – DynDNS Information
- Select Advanced Settings – Router – IP Passthrough – Enable/Check IP Passthrough
- Select Advanced Settings – Firewall – Enable Firewall – Disabled/Uncheck Enable Firewall