To configure GRE Tunnels:
1. In the configuration editor, navigate to Connections > Site > GRE Tunnels. The source IP address can only be chosen from the Virtual network interface on trusted links.
2. Enter a name for the GRE Tunnel.
3. Select the Source IP address available from the drop-down menu. The Routing Domain determines which Source IP Addresses are available from the drop-down menu.
4. (Optional) Select the Public Source IP. This field can be empty if this address is the same as Source IP.
5. Enter the Destination IP address of the GRE Tunnel.
6. Enter the Tunnel IP/Prefix address of the GRE Tunnel.
7. Click Checksum, if you want to use checksum in the GRE Tunnel Header.
8. Enter a value for the Keepalive Period in seconds. If you configure 0, no keepalive packet are transmitted, but the GRE Tunnel will be active.
9. Enter a value for the Keepalive Retries. This value determines the number of times the keepalive retries are attempted before the SD-WAN appliance deactivates the GRE Tunnel.
Refer to the configuring GRE tunnels on the MCN site for more information.
For more information about securing web gateway using GRE tunnels, see; Secure Web Gateway