Operation Manual

The VPN Protocol IPsec
40 NetWAYS/ISDN – 3 Remote Access with NetWAYS/ISDN
in the LAN using an internal IP address. The AVM Access
Server also provides the LAN with its gateway to the In-
ternet.
Remote Computer with NetWAYS/ISDN
When the VPN connection is active, the remote stand-
alone computer also has two IP addresses: its official IP
address that is valid in the Internet, and its IP address
in the virtual private network. The official IP address is
usually assigned dynamically by the Internet Service
Provider each time the Internet connection is dialed up.
This means the address can change with each new con-
nection. The IP address of the computer in the virtual
network is a private IP address in the company network.
This address is assigned by NetWAYS/ISDN before the
VPN connection is activated.
In the encapsulated packets transported over the IPsec tun-
nel between the NetWAYS/ISDN computer and the AVM Ac-
cess Server, different IP addresses appear in the original
packet’s IP header and in the encapsulating packet header:
IP addresses in the original packet
Destination The private IP address of the computer in the compa-
ny network that is the intended recipient of the com-
munication.
Source The remote computer's IP address in the virtual net-
work.
IP addresses in the tunnel packet
Destination The AVM Access Server’s official IP address in the
Internet.
Source The official, public IP address of the remote comput-
er in the Internet.
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