Overview of Secure VPN Implementation - Page 9
Overview of Secure VPN Implementation
IP Office’s secure VPN solutions comprise both IPSec and L2TP tunneling protocols.
Both of these protocols may be used independently or collectively to provide the
required secure VPN. In order to explain the IP Office secure VPN solution this section
describes each protocol implementation in turn and, for IPSec, how IP Office handles
an unprotected packet arriving at an interface.
IPSec Implementation
An inbound unprotected packet is one that is
not protected
by IPSec and is therefore
received on an interface outside an established IPSec tunnel. In the context of IPSec it
is an unsecured packet. If the inbound unprotected packet matches the condition on
any configured IPSec form then a Security Association (SA) is formed with the specified
Secure Gateway. Once the SA is established the inbound packet is secured and
forwarded to the Secure Gateway as an ESP packet.
Note:
IPSec implementation on IP Office requires a valid licence.
If the packet does not match any condition set on an IPSec configuration then it is
simply forwarded unencrypted to the appropriate destination interface. The diagram
below details the case for an inbound unprotected packet.
Figure 4. Inbound Unprotected Packet
If the unprotected packet matches the configured IP address condition for an
established SA it is forwarded to the destinations using the SA.
IP Office (R3.0) Virtual Private Networking
Overview of Secure VPN Implementation - Page 9
40DHB0002UKER Issue 3 (4th February 2005)
IPSec Implementation