The GRE configuration page allows you to create, configure, edit and delete GRE tunnels:

In this section:

Using the GRE Configuration Page

  1. Choose GRE from the Configuration Menu.

  2. To enable the GRE module globally, select Enable the GRE module checkbox and click Submit. If the box is not checked, no tunnels are available even if the individual tunnels themselves are enabled. 

  3. To refresh the status of all tunnels, click Refresh Status. If more information is available, an information icon is displayed to indicate the time the status event occurred, the IP address of the remote party, or detailed Help text, for example.

  4. The GRE Tunnels table allows you to manage tunnels on the system:

Adding a GRE Tunnel

To configure GRE on the secondary WAN interface and create a GRE tunnel:

  1. Choose GRE from the Configuration Menu.

  2. Click Add a new tunnel to open the Add New GRE Tunnel page. 

  3. Configure settings using the information in the following table as a guide.

    Add New GRE Tunnel Settings

    ItemDescription
    Tunnel Name

    Enter the name of the GRE tunnel.

    The name must be unique per device, with a maximum length of 15 characters. The tunnel name must start with an alphabetical character and can consist of characters (A-Z, a-z), digits (0-9), hyphen (-), period (.), and underscore (_).

    Enabled

    This is the individual disable/enable option for the tunnel. Select the Enabled checkbox to use the tunnel on the system now or leave the box unchecked to save the tunnel configuration for later.

    A disabled tunnel is counted towards the maximum number of allowed tunnels, which is four in this case. However, this allows you to save the tunnel configuration if the tunnel is needed at a later stage.

    InterfaceThis is the WAN interface over the tunnel to be created. This is WAN2 by default.
    Local GRE Gateway

    This is the WAN IP address over the tunnel to be created and will be the secondary WAN IP address by default.

    Ensure that the Local GRE Gateway of EdgeMarc is the same as the Remote GRE Gateway of peer device and vice versa.

    Remote GRE Gateway

    This is the WAN IP address of the peer end device. If it is an EdgeMarc, provide WAN2 address of the EdgeMarc. If it is another device, provide IP address of the interface that is connected to the WAN side.

    GRE Interface IP AddressThis is the IP address of the GRE interface. This address is for the tunnel interface created on the system and only has local significance. Ensure that this address does not conflict with the LAN and WAN addresses. 
    Network MaskThis is the network mask for the GRE interface IP address.
    TTLThis is the Time To Live (TTL) for the IP packet encapsulated in the GRE packet. Specify TTL within a range of 1 to 255.
    Enable Route Monitoring

    This is the enable/disable option for BGP route monitoring.

    When this checkbox is enabled, the WAN1 BGP status is monitored. Based on this status, the default gateway is switched between GRE over WAN2 or BGP over WAN1. When Route Monitoring is enabled and the changes saved, you can see the Route Status on the GRE Tunnel Settings page.

    Note: Only a single tunnel can be configured with route monitoring at a time. The Enable Route Monitoring option is hidden if it is already enabled for an active GRE tunnel.

    Enable KeepAlive

    The KeepAlive mechanism checks whether the GRE tunnel is up or down. KeepAlive Ping sends ICMP ping message to the WAN interface of peer device, through tunnel interface with GRE header in the KeepAlive packet. To get a reply for the KeepAlive ping message, static route must be added in peer device. If the peer device is an EdgeMarc, the static route is automatically installed for KeepAlive messages.

    If KeepAlive Ping is disabled, tunnel is always in an Established state and cannot get the run-time status even when the remote tunnel goes down. KeepAlive Ping is disabled by default.

    Note: You can enable KeepAlive Ping only if the peer device has a route to send ICMP reply to the EdgeMarc.

    Ping Interval (seconds)This is the interval between consecutive pings (in seconds). Specify a ping interval within the range 1-300.
    Up Ping AttemptsThis is the number of consecutive successful KeepAlive attempts before a tunnel link is considered UP.
    Down Ping AttemptsThis is the number of consecutive failed KeepAlive attempts before a tunnel link is considered DOWN.

    Once you are done configuring settings, click Submit to make your changes take effect. The GRE Tunnel Settings page will now show the Tunnel Status.

  4. GRE uses the route monitoring option to monitor BGP routes on the primary interface. When BGP fails on the primary interface, GRE detects this and GRE Default Gateway is installed on the system.
    When BGP is up and running the route status shows the Current Data Interface as WAN1. If BGP fails, the Current Data Interface changes to GRE.

Modifying a GRE Tunnel

To modify a GRE tunnel, follow the steps given below:

  1. Choose GRE from the Configuration Menu.

  2. In the GRE Tunnels table, click the GRE tunnel that you want to modify.

  3. Edit settings using the information in Add New GRE Tunnel Settings as a guide.

  4. Click Submit to save changes.
  5. Click Back to GRE overview to return to the GRE Configuration page.

Disabling a GRE Connection

To disable a GRE connection, follow the steps given below:

  1. Choose GRE from the Configuration Menu.

  2. Deselect the Enable the GRE module checkbox and click Submit. GRE is now disabled.

Deleting a GRE Tunnel

To delete a GRE tunnel, follow the steps given below:

  1. Choose GRE from the Configuration Menu.
  2. In the GRE Tunnels table, select the checkboxes corresponding to the GRE tunnel entries that you want to delete. Click All to select all entries or None to clear your selection.
  3. Click Delete. You are prompted to confirm the deletion.
  4. Click OK to confirm.