I’d be pretty willing to bet you’ve heard the term VPN more than once before. Maybe you even know what one is, but just in case, a virtual private network (VPN) allows the creation of private networks across the Internet, enabling privacy and tunneling of non-TCP/IP protocols.
VPNs are used daily to give remote users and disjointed networks connectivity over a public medium like the Internet instead of using more expensive permanent means.
Types of VPNs are named based upon the role they play in a business. There are three different categories of VPNs:
Remote access VPNs Remote access VPNs allow remote users like telecommuters to securely access the corporate network wherever and whenever they need to.
Site-to-site VPNs Site-to-site VPNs, or intranet VPNs, allow a company to connect its remote sites to the corporate backbone securely over a public medium like the Internet instead of requiring more expensive WAN connections like Frame Relay.
Extranet VPNs Extranet VPNs allow an organization’s suppliers, partners, and customers to be connected to the corporate network in a limited way for business-to-business (B2B) communications.
Now you’re interested, huh! And since VPNs are inexpensive and secure, I’m guessing you’re really jonesing to find out how VPNs are created right?. Well, there’s more than one way to bring a VPN into being. The first approach uses IPSec to create authentication and encryption services between endpoints on an IP network. The second way is via tunneling protocols, allowing you to establish a tunnel between endpoints on a network. And understand that the tunnel itself is a means for data or protocols to be encapsulated inside another protocol—pretty clean!
I’m going to go over the first, IPSec way in a minute, but first, I really want to describe four of the most common tunneling protocols in use:
Layer 2 Forwarding (L2F) Layer 2 Forwarding (L2F) is a Cisco-proprietary tunneling protocol, and it was their first tunneling protocol created for virtual private dial-up networks (VPDNs).
VPDN allows a device to use a dial-up connection to create a secure connection to a corporate network. L2F was later replaced by L2TP, which is backward compatible with L2F.
Point-to-Point Tunneling Protocol (PPTP) Point-to-Point Tunneling Protocol (PPTP) was created by Microsoft to allow the secure transfer of data from remote networks to the corporate network.
Layer 2 Tunneling Protocol (L2TP) Layer 2 Tunneling Protocol (L2TP) was created by Cisco and Microsoft to replace L2F and PPTP. L2TP merged the capabilities of both L2F and PPTP into one tunneling protocol.
Generic Routing Encapsulation (GRE) Generic Routing Encapsulation (GRE) is another Cisco-proprietary tunneling protocol. It forms virtual point-to-point links, allowing for a variety of protocols to be encapsulated in IP tunnels.
Okay—now that you’re clear on both exactly what a VPN is and the various types of VPNs available, it’s time to dive into IPSec.
VPNs are used daily to give remote users and disjointed networks connectivity over a public medium like the Internet instead of using more expensive permanent means.
Types of VPNs are named based upon the role they play in a business. There are three different categories of VPNs:
Remote access VPNs Remote access VPNs allow remote users like telecommuters to securely access the corporate network wherever and whenever they need to.
Site-to-site VPNs Site-to-site VPNs, or intranet VPNs, allow a company to connect its remote sites to the corporate backbone securely over a public medium like the Internet instead of requiring more expensive WAN connections like Frame Relay.
Extranet VPNs Extranet VPNs allow an organization’s suppliers, partners, and customers to be connected to the corporate network in a limited way for business-to-business (B2B) communications.
Now you’re interested, huh! And since VPNs are inexpensive and secure, I’m guessing you’re really jonesing to find out how VPNs are created right?. Well, there’s more than one way to bring a VPN into being. The first approach uses IPSec to create authentication and encryption services between endpoints on an IP network. The second way is via tunneling protocols, allowing you to establish a tunnel between endpoints on a network. And understand that the tunnel itself is a means for data or protocols to be encapsulated inside another protocol—pretty clean!
I’m going to go over the first, IPSec way in a minute, but first, I really want to describe four of the most common tunneling protocols in use:
Layer 2 Forwarding (L2F) Layer 2 Forwarding (L2F) is a Cisco-proprietary tunneling protocol, and it was their first tunneling protocol created for virtual private dial-up networks (VPDNs).
VPDN allows a device to use a dial-up connection to create a secure connection to a corporate network. L2F was later replaced by L2TP, which is backward compatible with L2F.
Point-to-Point Tunneling Protocol (PPTP) Point-to-Point Tunneling Protocol (PPTP) was created by Microsoft to allow the secure transfer of data from remote networks to the corporate network.
Layer 2 Tunneling Protocol (L2TP) Layer 2 Tunneling Protocol (L2TP) was created by Cisco and Microsoft to replace L2F and PPTP. L2TP merged the capabilities of both L2F and PPTP into one tunneling protocol.
Generic Routing Encapsulation (GRE) Generic Routing Encapsulation (GRE) is another Cisco-proprietary tunneling protocol. It forms virtual point-to-point links, allowing for a variety of protocols to be encapsulated in IP tunnels.
Okay—now that you’re clear on both exactly what a VPN is and the various types of VPNs available, it’s time to dive into IPSec.
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