4.3 Virtual Network Adapter
PacketiX VPN Client communicates over a VPN by creating a Virtual
Network Adapter on the system. The Virtual Network Adapter is recognized
by the Windows operating system and applications running on Windows as a
network device in the same way as a physical network adapter. This
enables the user to use the Virtual Network Adapter with TCP/IP
protocols and other network protocols (such as NetBEUI).
4.3.1 Support for Multiple Virtual Network Adapters
The earlier version of SoftEther 1.0 only allowed the user to create
one Virtual Network Adapter on the system. In PacketiX VPN Client 2.0,
however, multiple Virtual Network Adapters can be created on the system,
unique TCP/IP protocol settings can be configured for each Virtual
Network Adapter, and these Virtual Network Adapters can then connect to
the VPN simultaneously as individual network devices.
Figure 4-3-1 Support for Multiple Virtual Network Adapters |
4.3.2 Virtual Network Adapter Creation and Setup
Creating a Virtual Network Adapter
When the VPN client is first installed, there will be no Virtual
Network Adapters registered. The user can freely create as many Virtual
Network Adapters as needed.
Each new Virtual Network Adapter must be given a name. A name
consists of up to 31 alphanumeric characters. However, names are limited
to four characters under Windows 98 Second Edition and Windows
Millennium Edition. When multiple Virtual Network Adapters are created,
the Virtual Network Adapter names must all be different.
Only users with administrator privileges on the computer can change
Virtual Network Adapter settings. Only users who can connect to and
control the VPN client service on the computer can create or delete
Virtual Network Adapters.
To create a new Virtual Network Adapter, click [Create Virtual
Network Adapter] under [Virtual Adapter] menu in the VPN Client Manager.
Figure 4-3-2 New Virtual Network Adapter Creation Dialog |
Normal Virtual Network Adapter Settings
A newly created Virtual Network Adapter will be recognized as a
Windows device. It will be displayed as a [new network connection] icon
in [Network Connections] in the Windows Control Panel.
If, for example, the name of the newly created Virtual Network
Adapter was "ABC", that Virtual Network Adapter device name will
be registered and displayed as "VPN Client Adapter - ABC" in the
Device Manager. Also, the name of the icon registered in the Control
Panel's [Network Connection] window will be "ABC - VPN client".
The user can change this name at any time.
Figure 4-3-3 Virtual Network Adapter Display in Network
Connections |
The TCP/IP protocol and other settings for the Virtual Network
Adapter can be set in the same way a normal network adapter is set by
right clicking the VPN client Virtual Network Adapter's icon in the
Control Panel's [Network Connections] folder and selecting [Properties].
When a new Virtual Network Adapter was created, the user can set the
protocol and clear any unneeded service bindings in the same manner as
the user would for a physical network adapter. For details on the
settings, please ask the administrator for the VPN server you want to
connect to.
Figure 4-3-4 Virtual Network Adapter Network Properties |
Changing Advanced Settings
The following Virtual Network Adapter settings can be changed in the
properties for a VPN client Virtual Network Adapter registered in the
Windows Device Manager. Note that the VPN connection will be temporarily
closed if these settings have been changed while the Virtual Network
Adapter is being used for VPN communication.
| Item |
Description |
Default |
| Indicate Speed
(Mbps) |
Specifies the datalink speed in Mbps that the Virtual
Network Adapter reports to the operating system. Windows
recognizes that the maximum communication rate supported by
the Virtual Network Adapter is the value set here. The
actual communication rate is not influenced by the value set
here. Although normally no problems will occur if this
setting is left at 100 Mbps, if the physical connection used
for VPN communication have a maximum rate of only 10 Mbps,
this value may be set to 10 Mbps. |
100 (Mbps) |
| MAC Address |
Specifies the value of the MAC address held by the Virtual
Network Adapter. This item can be set to any value that can
be used as a MAC address. When specifying a MAC address,
specify a consecutive sequence of hexadecimal digits. (No
hyphens or colons are required.) |
A 4-byte value that consists of "00:AC" (fixed) followed by
a random number is used as the initial MAC address.
|
Figure 4-3-5 Virtual Network Adapter Device Driver Setting
Window |
Removing a Virtual Network Adapter
Once a Virtual Network Adapter has been added by the user, it remains
in the system until the user removes it manually. There are two ways to
remove a Virtual Network Adapter as shown below. These methods for
removing a Virtual Network Adapter are equivalent.
- Removal using the Windows Device Manager
- Removal using the VPN Client Manager
Enabling and Disabling a Virtual Network Adapter
A Virtual Network Adapter registered in the system can be enabled or
disabled at any time. When a new Virtual Network Adapter is created, it
will be in the enabled state. When a Virtual Network Adapter is
disabled, Windows handles it as though it has been disconnected from the
system.
The Virtual Network Adapter enable/disable operations are performed
from either the VPN Client Manager or the Windows Device Manager or
[Network Connections] window.
Figure 4-3-6 Disabling a Virtual Network Adapter |
Messages Indicating that a Network Cable is Unplugged
Under Windows 2000 and later, when a new Virtual Network Adapter is
created, an icon is displayed in the task tray at the lower right of the
task bar and "A network cable is unplugged." message is displayed. This
is normal operation.
When a VPN client uses a Virtual Network Adapter which is not
connected to a VPN, the adapter operates in exactly the same state as
when the network cable between a physical network adapter and the
switching hub is disconnected. Therefore when a Virtual Network Adapter
is used and a VPN is not connected, Windows handles that Virtual Network
Adapter as a network adapter to which no network cable is attached. When
a VPN connection is established using Virtual Network Adapter, the
operation will start in the same fashion just as when a network adapter
is connected to a switching hub by a network cable.
Figure 4-3-7 The "A network cable is unplugged" Message |
Figure 4-3-8 Virtual Network Adapter's "Connection
Established" Message |
4.3.3 Managing the Version of the Virtual Network Adapter Device
Driver
The version of the device driver of the Virtual Network Adapter
created by the user is displayed in VPN Client Manager. This is the
version of the device driver program file at the time the user
registered the Virtual Network Adapter to Windows.
The version of the device driver of the Virtual Network Adapter is
the same as the version of the VPN Client software used to create the
Virtual Network Adapter. Even if a later version of the VPN Client
software is installed thereafter, the version of the device driver of
the previously created Virtual Network Adapter is not updated. To update
the version of the device driver of the Virtual Network Adapter to the
same version of the VPN Client software, use VPN Client Manager to
select the Virtual Network Adapter to be updated and click [Reinstall
Driver] on the [Virtual Adapter] menu.
4.3.4 Bridge Connection Between a Virtual Network Adapter and
Physical Network Adapter
In SoftEther 1.0, it was possible to connect a virtual network to a
physical network using the Windows function to create a bridge
connection between the Virtual Network Adapter and physical network
adapter.
In PacketiX VPN 2.0, the user can create a local bridge connection
between a Virtual HUB and an existing physical LAN with the functions
provided in VPN Server and VPN Bridge. (For details, please refer to
「3.6 Local Bridges」.)Because the performance of the local bridge connection function
of VPN Server / VPN Bridge is the same as or better than that when using
VPN Client together with the bridge connection function of Windows
XP/Server 2003/Vista, normally, there is no need to use the bridge
connection function on the client side.
Under special circumstances or when the user wants to create a bridge
connection between the Virtual Network Adapter and physical network
adapter on the VPN Client side, a bridge connection can be created in
the same way as the Virtual Network Adapter of SoftEther 1.0. In these
cases, connect the Virtual Network Adapter and the physical network
adapter using the same method for creating a bridge connection between
two network adapters using the functions of Windows XP/Server
2003/Vista.
Figure 4.3.9 Using the Windows Function to Create a Bridge
Connection Between a Virtual Network Adapter and Physical
Network Adapter |
|