PPTP
Point-To-Point-Tunneling
Protocol (PPTP) is the most popularly VPN protocol and is supported by
the most devices. PPTP stands for point to point protocol, is by far the
easiest to configure and has low overhead that makes it faster than
other VPN protocols. Firewalls such as ISA Server, Cisco PIX and Sonic
Wall recognize the protocol.
PPTP
encrypts data using a 128-bit key which puts it in the “weakest”
category of VPN protocols. It has also had other weaknesses in the past,
such as clear-text authentication prior to a connection being
established and as such it is rarely used in sensitive business
environments. However, the most recent implementations of this protocol
have resolved some of the security issues – for example, the
implementation of EAP authentication.
L2TP/IPSec
Layer 2 Tunneling Protocol (L2TP) came
about through a partnership between Cisco and Microsoft with the
intention of providing a more secure VPN protocol. L2TP is considered to
be a more secure option than PPTP, as the IPSec protocol which holds
more secure encryption algorithms, is utilized in conjunction with it.
It also requires a pre-shared certificate or key. L2TP’s strongest level
of encryption makes use of 168 bit keys, 3 DES encryption algorithm and
requires two levels of authentication.
L2TP
has a number of advantages in comparison to PPTP in terms of providing
data integrity and authentication of origin verification designed to
keep hackers from compromising the system. However, the increased
overhead required to manage this elevated security means that it
performs at a slower pace than PPTP.
SSTP
Secure Socket Tunneling Protocol (SSTP) is
viewed as the VPN protocol with the highest security due to
authenticating with 2048 bit key certificates and encrypting with 256
bit key. SSTP can be used in place of other VPN protocols (PPTP, L2TP),
and is effective in locations where network access is restricted as it
uses TCP port 443, the same port used by Secure Socket Layer (SSL)
transmissions.
SSTP
VPN is viewed as quicker and more reliable than OpenVPN. However, your
operating system needs to be relatively up to date in order for it to
function properly with SSTP.
The
major disadvantage of SSTP is that since it was developed by Microsoft
it only functions on Windows Vista / Windows 7 / Windows 8. Currently,
there are no intentions to make the protocol available to users of Mac
OS, Linux and older versions of Windows.
OpenVPN
OpenVPN
was developed by Open Source software as a free alternative to
Microsoft’s SSTP protocol. One major advantage of this particular
protocol is that it functions on a variety of operating systems, such
as, Mac OS, Windows, Linux and some IP phones. Similar to SSTP, OpenVPN
has a higher encryption level than L2TP as it operates on both Layer 2
and Layer 3. Furthermore, it is accompanied with extra features such
as transporting Ethernet frames, IPX packets and providing NETBIOS
functionality.
A
minor disadvantage with OpenVPN is that it provides insufficient
support for mobile devices and the requirement to install a 3rd party
client. This is not the case for SSTP.
A
major disadvantage with VPN is the high overhead associated with the
protocol due to its level of encryption. It may also be quite
challenging to configure.
