The GRE configuration on your HPBX phone system's router automatically redirects voice traffic through a data connection or backup connection if the primary Internet connection goes down. This ensures you can still make calls while we work on repairing the HPBX phone system's Internet connection.
Begin the setup by connecting an Ethernet cable from either G2 or G3 on the Primus POE switch (if G2 is being used to connect another POE switch) to your DATA network modem/router or Firewall.
In order for us to set up the GRE, we will need the following IP address information, which applies to 90% of cases and includes a shared Public IP:
1- Public IP of your Internet Connection (must be static)
2- IP to assign to the HPBX 1841 Router (must be static)
3- IP of internal Gateway
5- Subnet Mask of Internal Network
Make sure to adjust these settings in your firewall:
1- Enable GRE (Protocol 47 - GRE is protocol 47 not port 47. On most routers you are looking for "enable PPPTP pass-through"; some it is simply VPN pass-through, others it is not supported)
2- Open port 500 UDP (IKE)
3- Open port 4500 UDP (NAT-T)
4- IP address to be white-listed: 216.254.130.150 (East) & 209.90.160.50 (West)