Lancom Systems LCOS 3.50 - Manual (Page 300)

LANCOM Reference Manual LCOS 3.50 ̈ Chapter 14: Virtual Private Networks—VPN
300
V
irt
ua
l Pri
vat
e Ne
two
rks—
VP
N
software then sets up a tunnel to the VPN gateway of the LAN using this
Internet connection.
The VPN gateway of the LAN must support the establishment of VPN tunnels
with the VPN client software of the remote PC.
14.4 What is LANCOM Dynamic VPN?
LANCOM Dynamic VPN is a patent-pending LANCOM Systems technology
which permits VPN tunnels to be connected to remote stations that do not
have a static, but only a dynamic IP address.
Who needs LANCOM Dynamic VPN and how does it work? We will answer this
question in two steps: First, a look at the basics of IP addressing will show the
problem of static IP addresses. The second step shows the solution thereof
with LANCOM Dynamic VPN.
14.4.1 A look at IP addressing
Every participant on the Internet needs an IP address. Participants even need
a special kind of IP address - a public one. The administration of public IP
addresses is handled from central locations in the Internet. Each public IP
address may only occur once on the entire Internet.
Local IP-based networks do not use public, but private IP addresses. For this
reason, a number of address ranges within the entire IP address range have
been reserved for private IP addresses.
A computer connected to both a local network and directly to the Internet
therefore has two IP addresses: a public one for communication with the rest
Internet
Headquarters
LAN
Remote computer
with VPN client
Laptop with
VPN client