VPNs

[groovin]

Ive worked with frame relay WANs and some ATMs... basically they are just leased lines through some big ISP that has some bandwidth constraints (although burstable) and frame relay and such are just technologies (encapsulation methods) that you use on that line.

is VPN the same thing basically? can someone give me a sort of description on how it works? thanks

 

[Rainsford]

VPN is Virtual Private Network. It allows two seperate networks to become virtually connected in a secure manner. For example, let's say a company has a headquarters and two branch officers. The branch officers get some kind of connection to a local ISP (DSL, T1, whatever, it makes no difference). That connection allows them full access to the internet. Now they also have some hardware which connects through the internet to hardware at the home office (which also has an internet connection). Now the offices are connected as if they had a direct leased line between them.

 

[groovin]

i see... so theres basically machines on both ends that act as clients and servers for the VPN using PPTP?

 

[cmetz]

groovin, first of all, VPN is a marketing term that is used by different people to mean different things. For example, some marketing folks will call the frame and/or ATM networks with VCs you've used before "VPN"s. Frequently, VPN is used to refer to IPsec ESP tunnels, which can as a very rough concept be thought of as point-to-point virtual circuits that use the public Internet as the low-level transport. IPsec ESP tunnels are typically encrypted and integrity protected, which is a nice bit of security. A router that can be an IPsec ESP / IKE endpoint is typically called a "VPN gateway" or something like that, but it's basically just a router with encryption.

The main upsides to an IPsec ESP VPN are that they're cheap (just use commodity IP bandwidth) and fairly easy to set up (well, no fighting with telcos ) and encrypted. The main downsides to an IPsec ESP VPN are that they are less reliable than a truly private network (again because they use commodity bandwidth) and that the current implementations and the IKE protocol are more complicated then they should be.

PPTP could also be called a VPN technology, but you simply shouldn't be using it.