GRE allows you to creat point-to-point tunnel, it's unsecure, IPsec is a protocol represents to Internet Protocol securre, and you can use it in your traffic while using GRE tunnel. So, you can encrypt and secure your date the send through GRE tunnel using IPsec

Understanding Cisco Dynamic Multipoint VPN - DMVPN, mGRE, … The diagram below shows a point-to-point GRE VPN network. All spokes connect directly to the hub using a tunnel interface. The hub router is configured with three separate tunnel interfaces, one for each spoke: Each GRE tunnel between the hub-spoke routers is configured with its unique network ID. Point-to-Point Tunneling Protocol - Wikipedia The Point-to-Point Tunneling Protocol (PPTP) is an obsolete method for implementing virtual private networks.PPTP has many well known security issues. PPTP uses a TCP control channel and a Generic Routing Encapsulation tunnel to encapsulate PPP packets. Many modern VPNs use various forms of UDP for this same functionality.. The PPTP specification does not describe encryption or authentication

By Tim Charlton. IP Security (IPSec) Virtual Private Networks (VPNs) and Generic Routing Encapsulation (GRE) tunnels are both methods for transferring data across public, intermediary networks, such as the Internet. However, there are considerable differences between the two technologies. Let’s start with a brief overview.

Site-to-Site IPsec VPN Deployments and GRE (IPsec+GRE) At the core of IPsec is point-to-point functionality, which is not suited for all of today's IP communications. Indeed, many of today's voice and video applications require point-tomultipoint connectivity.

GRE can be used with: - Connecting IPv6 networks over IPv4 networks - Multicast packets, such as OSPF, EIGRP, and streaming applications 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.

Configuration Configuration Difficulty: Intermediate Router A: GRE Configuration. Step 1: Log into the router's NCOS Page. For help with logging in please click NCOS: Accessing the Setup Pages of a Cradlepoint router.; Step 2: Click Networking then Tunnels then GRE.; Step 3: Click the Add button to create a new GRE Tunnel.; Step 4: Give the Tunnel a Name for easy identification. GRE tunnel vs. IPsec tunnel - Cisco & Cisco Network VPN gateway "A" encrypts the private IP packet and relays it over an ESP tunnel to a peer VPN gateway at the edge of network "B." VPN gateway "B" then decrypts the packet and delivers it to the destination host. Like GRE, it doesn't really matter how the two VPN gateways communicate with each other -- hops in between just pass along the ESP packet. VPN Interface GRE - Viptela Documentation Create a VPN feature template to advertise a service that is reachable via a GRE tunnel, to configure GRE-specific static routes, and to configure other VPN parameters. See the VPN help topic. Create a data policy on the vSmart controller that applies to the service VPN, including a …