This design guide defines the comprehensive functional components required to build a site-to-site virtual private network (VPN) system in the context of enterprise wide area network (WAN) connectivity. This design guide covers the design topology of point-to-point (p2p) Generic Route Encapsulation (GRE) over IP Security (IPsec).

Generic Routing Encapsulation (GRE), defined by RFC 2784, is a simple IP packet encapsulation protocol. 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. This design guide defines the comprehensive functional components required to build a site-to-site virtual private network (VPN) system in the context of enterprise wide area network (WAN) connectivity. This design guide covers the design topology of point-to-point (p2p) Generic Route Encapsulation (GRE) over IP Security (IPsec). Generic Routing Encapsulation (GRE), on the other hand, is a tunneling protocol that is used to carry other routed protocols in an IP network as well as IP packets in an IP network. It is stateless and has no flow control mechanisms. While IPsec offers confidentiality through authentication, GRE offers less security. Oct 15, 2014 · GRE VPN Tunnel Overview In this Packet Tracer 6.1 activity you configure a Generic Routing Encapsulation (GRE) over IP VPN tunnel. VPN tunnels are now part of the CCNA certification exam. VPN tunnels allow geographically separate private local area networks to be connected to each other across public wide area networks. GRE tunnels can carry multicast packets—just like real network interfaces—as opposed to using IPSec by itself, which can't encrypt multicast traffic. Some examples of multicast traffic are OSPF, EIGRP, and RIPV2. Nov 18, 2015 · GRE Tunnel Configuration. A GRE tunnel is established on a router level and differs depending on the hardware type or service you use. Typically you’ll be required to set up the tunnel interface IPs and provide public IP addresses for both ends of the GRE tunnel. Here is an example of a tunnel set up between two Cisco routers: GRE based tunnels enable connectivity between tenant virtual networks and external networks. Since the GRE protocol is lightweight and support for GRE is available on most of network devices it becomes an ideal choice for tunneling where the encryption of data is not required.

You will use GRE/IPSEC with Tunnel Mode to accomplish this task. Because you need to totally cross-eliminate crypto ACLs, you can configure a GRE tunnel and encrypt all traffic that traverses the tunnel. Let’s configure it: Step 1. Configure the GRE tunnels.

Jul 16, 2019 · Click Add to select the VPN profile we just created and give the Weight (Only the VPN profile with GRE setting will be listed here.) Apply the settings. 4. Create a VPN Load Balance Rule: Go to VPN and Remote Access >> VPN Trunk Management >> Load Balance Rule, then click Add to create a new one. Input Profile Name. Select ALL for Protocol. Nov 21, 2019 · But yes, if you had another external device that could do multicast routing you could GRE tunnel it between two endpoints through the AutoVPN tunnel. This could be either a L2 or L3 GRE depending on how you wanted to do it. Unfortunately, Meraki does not support GRE, so you need to look elsewhere for that. May 05, 2017 · The tunnel interface adds GRE header to the packet and the outer IP header with the source IP address 1.1.1.1 and the destination IP address 1.1.1.2. The route 1.1.1.2/32 is looked up in the routing table of CE1.

Nov 18, 2015 · GRE Tunnel Configuration. A GRE tunnel is established on a router level and differs depending on the hardware type or service you use. Typically you’ll be required to set up the tunnel interface IPs and provide public IP addresses for both ends of the GRE tunnel. Here is an example of a tunnel set up between two Cisco routers:

GRE encapsulation supports any OSI Layer 3 protocol. GRE is stateless. GRE does not have strong security mechanisms. The GRE header alone adds at least 24 bytes of overhead. GRE provides flow control by default. GRE is the most secure tunneling protocol. NOTE:The GRE tunnel can also be routed over a Policy-Based IPsec Site-to-Site VPN. To do this, create loopback interfaces and exchange the local and remote IP addresses of the GRE tunnel using IPsec. Generic Routing Encapsulation (GRE) is one example of a basic, nonsecure, site-to-site VPN tunneling protocol. GRE is a tunneling protocol developed by Cisco that can encapsulate a wide variety of protocol packet types inside IP tunnels. GRE creates a virtual point-to-point link to Cisco routers at remote points, over an IP internetwork. In this lab, you will configure an unencrypted point-to-point GRE VPN tunnel and verify that network traffic is using the tunnel. You will also configure the OSPF routing protocol inside the GRE VPN tunnel. The GRE tunnel is between the WEST and EAST routers in OSPF area 0. The ISP has no knowledge of the GRE tunnel. Integrating p2p GRE with either IPsec tunnel mode or transport mode has been debated. Tunnel mode adds an additional 20 bytes to the total packet size. Either tunnel or transport mode work in a p2p GRE over IPsec implementation; however, several restrictions with transport mode should be considered. Jan 21, 2020 · A GRE tunnel capable of tunneling both IPv4 and IPv6 simultaneously has been configured with 102.1.1.0/24 as the overlay network. The 12.1.1.0/24 and 23.1.1.0/24 networks form the transport (underlay) connecting R1 and R2 to the public internet. The tunnel endpoints are the loopback interfaces 1.1.1.1/32 and 2.2.2.2/32 on R1 and R2 respectively. You use a Site-to-Site VPN connection to connect your remote network to a VPC. Each Site-to-Site VPN connection has two tunnels, with each tunnel using a unique virtual private gateway public IP address. It is important to configure both tunnels for redundancy.