How do I create a tunnel between two Cisco routers?

Let us examine each of the above steps.

Table of Contents

Step 1: Creating Extended ACL. Next step is to create an access-list and define the traffic we would like the router to pass through the VPN tunnel.
Step 2: Create IPSec Transform (ISAKMP Phase 2 policy)
Step 3: Create Crypto Map.
Step 4: Apply Crypto Map to the Public Interface.

How do I create a Cisco GRE tunnel?

There are five steps to configuring a GRE tunnel:

Create a tunnel interface using the interface tunnel number global configuration command.
Configure an IP address for the tunnel interface using the ip address ip-address interface configuration command.

What is tunnel mode GRE IP?

Enables generic routing encapsulation (GRE) over on a tunnel interface and specifies that the tunneling protocol is IPv4.

What is IPSec over GRE?

IPSec over GRE technology uses GRE to encapsulate packets that have been encapsulated using IPSec. IPSec over GRE implements IPSec encryption on tunnel interfaces. The system detects data flows that need to be encrypted on tunnel interfaces (an ACL is configured to match data flows between two user network segments).

How do I build IPSec tunnel?

Preshared key authentication

In the administration interface, go to Interfaces.
Click Add > VPN Tunnel.
Type a name of the new tunnel.
Set the tunnel as active and type the hostname of the remote endpoint.
Select Type: IPsec.
Select Preshared key and type the key.

Why GRE tunnel is not secure?

Generic Routing Encapsulation (GRE) is used when IP packets need to be sent from one network to another, without being parsed or treated like IP packets by any intervening routers. However, they are not secure, does not provide encryption. With GRE we can configure a virtual tunnel between two endpoints.

How do you set up tunnels?

There are three necessary steps in configuring a tunnel interface:

1 Specify the tunnel interface—interface tunnel-ipsec identifier.
2 Configure the tunnel source—tunnel source {ip-address | interface-id }
3 Configure the tunnel destination—tunnel destination {ip-address | tunnel-id }

How is a GRE tunnel established?

Encapsulating packets within other packets is called “tunneling.” GRE tunnels are usually configured between two routers, with each router acting like one end of the tunnel. The routers are set up to send and receive GRE packets directly to each other.

How is a GRE tunnel formed?

The first step is to create the logical interface for the tunnel. In Cisco IOS, tunnels are formed using tunnel interfaces. Tunnel interfaces are virtual interfaces that act as if they are directly connected interfaces and are created using the interface tunnel [tunnel interface number] global configuration command.

Why GRE tunnel is required?

Overview of GRE For example, GRE tunnels allow routing protocols such as RIP and OSPF to forward data packets from one switch to another switch across the Internet. In addition, GRE tunnels can encapsulate multicast data streams for transmission over the Internet.

How do I create a tunnel network?

Step 1 (Windows) — Setting Up the Tunnel

From the Session section, add the Host Name (or IP address) of your server, and the SSH Port (typically 22)
On the left, navigate to: Connection > SSH > Tunnels.
Enter any Source port number between 1025 and 65536 , such as 1337.
Select the Dynamic radio button.
Click the Add button.

How would you make GRE tunnel secure?

Click Create a secure GRE tunnel.
Click Enable to enable the configuration and complete the following: For GRE Tunnel Information. Interface Name. Enter the name of the interface to connect to tunnel. Tunnel Source. Select the tunnel source (WAN1, WAN2, USB1, or USB2) from the drop-down list.
Click Apply.

How does a GRE tunnel work?

GRE works by encapsulating a payload — that is, an inner packet that needs to be delivered to a destination network — inside an outer IP packet. GRE tunnel endpoints send payloads through GRE tunnels by routing encapsulated packets through intervening IP networks.

What is GRE tunnel in router?

Generic Routing Encapsulation (GRE) is a protocol that encapsulates packets in order to route other protocols over IP networks. GRE is defined by RFC 2784. GRE was developed as a tunneling tool meant to carry any OSI Layer 3 protocol over an IP network.

What is the purpose of GRE tunnels?

Generic routing encapsulation (GRE) provides a private path for transporting packets through an otherwise public network by encapsulating (or tunneling) the packets. GRE tunneling is accomplished through tunnel endpoints that encapsulate or de-encapsulate traffic.