> ## Documentation Index
> Fetch the complete documentation index at: https://docs.aviatrix.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Edge Transit Gateway External Connection Workflow

> This document describes how to connect an Edge gateway in hybrid or multicloud environment to an on-premises remote device, such as a remote router or firewall that terminate VPN connection.

This document describes how to connect an Edge gateway in hybrid or multicloud
environment to an on-premises remote device, such as a remote router or firewall
that terminate VPN connection.

## Configuration Workflow

To build an external connection (S2C) between an Edge gateway and an external
remote device, you need to configure one side of the tunnel connection on the
Edge gateway and the other side of the tunnel connection on the remote device.

To create an external connection:

1. [Configure the tunnel on the Edge gateway](#configure-the-tunnel-on-the-edge-gateway).
2. [Download the Edge gateway tunnel configuration file](#download-an-external-connection-configuration).
3. [Configure the tunnel on the remote device](#configure-the-tunnel-on-the-remote-device).
4. [Verify the connection is up](#verify-the-connection-status).

<a id="configure-bgp-tunnel-on-edge-transit-gateway" />

### Configure the Tunnel on the Edge Gateway

For BGP connection to the remote device, configure the tunnel using one of the
options below:

* [BGP over IPsec](https://legacy.docs.aviatrix.com/documentation/latest/network/external-connection-create-bgp-over-ipsec.html)
* [BGP over GRE](https://legacy.docs.aviatrix.com/documentation/latest/network/external-connection-create-bgp-over-gre.html)
* [BGP over LAN](https://legacy.docs.aviatrix.com/documentation/latest/network/external-connection-create-bgp-over-lan.html)

&#x20;&#x20;

<a id="download-tunnel-configuration" />

&#x20;

&#x20;

&#x20;

&#x20;

&#x20;

&#x20;

&#x20;

&#x20;

&#x20;

&#x20;

&#x20;

&#x20;

&#x20;

&#x20;

&#x20;

&#x20;
&#x20;

&#x20;

&#x20;

&#x20;

&#x20;

&#x20;

&#x20;

&#x20;
&#x20;

&#x20;

&#x20;
&#x20;
&#x20;
&#x20;

### Download an External Connection Configuration

If you are connecting an Aviatrix gateway and an on-premises router or firewall,
Aviatrix can generate a configuration file that you can apply to your remote
router or firewall. The configuration file contains the Aviatrix gateway tunnel
details, such as the Public IPv4 and IPv6 addresses, VPC/VNet CIDR, pre-shared
key, and encryption algorithm. You can download the configuration file and then
import the details to your remote router or firewall to configure the other end
of the VPN tunnel.

After creating an external connection, to download an external connection
configuration:

1. In Aviatrix CoPilot, go to **Networking > Connectivity > External Connections
   (S2C)** tab.

2. On the External Connections (S2C) tab, locate the connection you created and
   click the vertical ellipsis <img src={"/docs/enterprise/" + "10.1" +
   "/guides/connectivity/vpn/images/vertical-ellipsis-icon.png"} alt="vertical
   ellipsis icon" style={{display: 'inline', verticalAlign: 'middle', height: '1em'}} /> icon
   on the right side of the row.

3. Select the following values:
   * **Vendor**: Select your remote site device.
     * Select **Generic** for anything that is not an Aviatrix gateway.
     * Select **Aviatrix**, if you are connecting two Aviatrix gateways.
   * **Platform and Software**:
     * If you selected a Generic vendor, the Platform field is populated as
       Generic, and the Software field is populated with Vendor Independent.
     * If you selected the Aviatrix vendor, the Platform field is populated with
       UCC, and the Software version is 1.0.
     * If you selected a specific hardware vendor (such as Cisco), select from
       the available platforms belonging to that vendor are displayed in the
       Platform field (ISR, ASR, and CSR are for Cisco routers), and the
       Software field is populated with the related software version.

4. Click **Download**.

<a id="configure-tunnel-on-external-device" />

### Configure the Tunnel on the Remote Device

On the external remote device, configure the other end of the tunnel by using
the Edge gateway's connection details provided in the configuration file which
you downloaded. If you need to download the configuration file, refer to
[Download the External Connection Configuration](#download-an-external-connection-configuration).

&#x20;

<a id="verify-bgp-session" />

### Verify the Connection Status

To verify the connection status:

1. In CoPilot, go to **Diagnostics > Cloud Routes > External Connections** tab.
2. In the table, locate the connection that you created. The **Status** should
   be **Established**.

If the connection is not established, you can run

<a href={"/docs/enterprise/" + "10.1" + "/reference/ui/diagnostics/diagnostic-tools#run-connectivity-analysis"}>diagnostics</a>
to perform an analysis or review logs.

To troubleshoot issues with BGP connections, you can go to **Diagnostics >
Diagnostics Tools > BGP Diagnostics** tab and run BGP commands to retrieve BGP
information from the Edge Transit Gateway.

## Disconnect the External Connection

To disconnect an external connection:

1. In Aviatrix CoPilot, go to **Networking > Connectivity > External Connections
   (S2C)** tab.
2. In the table, locate the external connection and click the Delete icon <img src="https://mintcdn.com/aviatrix-14b37c43/DtLW-mqMRi95qZN9/images/guides/connectivity/edge/delete-icon.png?fit=max&auto=format&n=DtLW-mqMRi95qZN9&q=85&s=53573a210df48afba2fc09ced51e8fac" alt="delete icon" style={{display: 'inline', verticalAlign: 'middle', height: '1em'}} width="26" height="26" data-path="images/guides/connectivity/edge/delete-icon.png" /> on the
   right side of the row.
3. To confirm that you want to delete the external connection, click **Delete**.

The external connection is deleted.