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Whats the difference between using SSL/TLS in a web browser and an actual SSL/TLS VPN?

Is SSL/TLS actually the pure technology and when one uses https:// in a browser this is a vpn connection?

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3 Answers

SSL and its successor TLS is just a generic security layer for other protocols; you could say "the pure technology". But it is not a VPN by itself – HTTP and VPN are two distinct applications of TLS.

  • HTTPS is HTTP secured using TLS.
  • SMTPS is SMTP – a mail transfer protocol – secured using TLS.
  • FTPS is FTP secured using TLS.
  • OpenVPN is a VPN protocol secured using TLS.
  • SSTP is another VPN protocol secured using TLS.

And so on.

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Hi, so how does one make a VPN from TLS? Surely TLS has encryption just like a VPN too? I cant see how a VPN is different. –  William Dec 31 '11 at 0:58
    
@Levy: The word "VPN" means "virtual private network" -- creating a network out of distant hosts, nothing more. It does not imply encryption or even authentication of any sort. Look at, for example, L2TP -- it is purely a VPN protocol, with no encryption, relying on IPsec to provide it. Likewise, the OpenVPN and SSTP protocols by itself have no encryption, they both rely on TLS for encryption and even authentication. –  grawity Dec 31 '11 at 1:14
    
A VPN is much more complex than TLS alone - it actually simulates a network (hence the name), while TLS only provides a single connection. –  sleske Dec 31 '11 at 1:18
    
In somewhat other words: TLS provides encryption for arbitrary data streams, no matter what kind. The various VPN protocols link two networks, but do not necessarily have any protection. When someone says "SSL/TLS VPN", they usually mean a VPN protocol that is carried inside SSL/TLS. (There indeed are VPN protocols that provide security by themselves, but they usually suck -- such as PPP. Because of this, various Internet protocols tend to just do their own thing.) –  grawity Dec 31 '11 at 1:22
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The two uses are very similar but the very large difference is what traffic is actually sent securely. TLS is a point-to-point communication encryption mechanism, and can be used in a variety of applications for securing traffic (HTTPS, SMTPS, POP3S, and so on).

A TLS-based VPN is another such usage that allows for otherwise non-encrypted traffic to travel down an encrypted path. The main application is to secure traffic between a remote site and a local resource, such as a company intranet.

The VPN can be configured to only route (secure) traffic destined for the remote site down the VPN, or the remote site can act as a gateway for the local workstation and thus encrypting all traffic between that workstation and the VPN router.

Like other VPN technologies, a TLS-based VPN will encapsulate the underlying data into TLS-encrypted packets. This means that for instance you can have TLS-encrypted VPN packets which are in turn TLS-encrypted HTTP packets-- this is because the VPN acts a lower level in the OSI model stack.

If you are still unclear on the difference, do some further reading on the purpose and implementation of a VPN (generic, doesn't matter if it's TLS or PPTP or L2TP): VPN.

You can also read up on OpenVPN, which is the most popular SSL (TLS)-based VPN implementation.

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I think some of the other comments may have explained this more eloquently than I have however hopefully my description is useful for someone out there! –  Garrett Dec 31 '11 at 1:27
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SSL/TLS are cryptographic protocols.

A VPN is a network connection that selects and uses one type of cryptographic protocol to protect the connection. SSL/TLS is just one of many protocols that a VPN can use to protect the network traffic.

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