5.2 Operating Modes
The user can operate the PacketiX VPN Bridge in two modes: Service
Mode and User Mode. Below is an explanation of these two modes.
5.2.1 Service Mode
Service Mode is the normal operating mode. Installing and operating
the PacketiX VPN Bridge in Service Mode will cause the PacketiX VPN
Bridge to operate in the background as a part of the OS, launch when the
OS launches prior to user log in and await VPN session connection as the
VPN Bridge . In addition, the server will automatically shutdown when the
operating system shuts down.
The word "service" here refers to a background system service in
Windows and some UNIX operating systems and is sometimes referred to as
a daemon in other operating systems.
When the VPN Bridge is operating in Service Mode, said operation is
not depended upon by users currently logged onto the operating system.
That is why we recommend running the VPN Bridge in Service Mode on most
occasions.
When using the VPN Bridge in Service Mode, the VPN Bridge process
(executable file name vpnbridge ) typically runs on system or root
authority.
| The executable file name for the
32-bit Windows version PacketiX VPN Bridge is "vpnbridge .exe",
while the file name for the 64-bit version is
"vpnbridge _x64.exe". The description in this manual assumes use
of the 32-bit version, so please apply the relevant changes in
the case of the 64-bit version. |
Installing the VPN Bridgein Service Mode
The method for installing the VPN Bridge in Service Mode on the
Windows version differs to that of other UNIX versions.
Service Mode cannot be used in the following situations, in which
case the VPN Bridge should be used in User Mode.
- When the system on which the PacketiX VPN Bridge is to operate
does not have System Administrator authority.
- When the client wishes to install and use the PacketiX VPN
Bridge temporarily rather than continuously.
- When the client wishes to launch the PacketiX VPN Bridge with
general user authority for security reasons.
Service Mode for Windows Version PacketiX VPN Bridge
We recommend using the installer when installing the Windows version
VPN Bridge in Service Mode. This method automatically launches and runs
the VPN Bridge as a service without the need for any special operation
by the client. Even if the system is rebooted, the VPN Bridge will
automatically begin operating upon system start-up. Because the VPN
Bridge is launched as a background task, the computer on which the
server is installed can be used for other tasks without the client
having to be aware of said server's installation.
In addition, the Windows version PacketiX VPN Bridge service can be
commenced or terminated by attaching the relevant command line argument
to the executable file name (vpnbridge .exe), or can be removed or
re-registered from the Windows system via the Windows system service
list.
The shortened service name of the PacketiX VPN Bridge service
registered on the Windows system is "vpnbridge " and the long
service name is
"PacketiX VPN Bridge ".
In order to register vpnbridge .exe as a service when the PacketiX
VPN Bridge service is not currently installed on the Windows system, insert
the following from the command prompt and execute vpnbridge .exe (System
Administrator authority is required).
To delete the PacketiX VPN Bridge service when it is already
installed on the Windows system, insert the following from the command
prompt and execute vpnbridge .exe (System Administrator authority is
required).
Furthermore, attaching the /start or /stop arguments
enables the service to be commenced or terminated. For details on other
arguments which can be designated in the vpnbridge program, please refer
to the message box which appears when directly executing vpnbridge .exe.
The service can also be started and terminated by accessing [Control
Panel] > [Administrative Tools] > [Services] (or [Control Panel] >
[Services] in the case of Windows NT 4.0). It is possible to change the
server from [Automatic] to [Manual] startup by selecting PacketiX VPN
Bridge from the [Services] list, then clicking open [Startup type].
Changing the startup type to [Manual] means that the service does not
launch automatically on startup, and does not operate until initiated by
a user with Administrator authority.
It is also possible to start and stop the PacketiX VPN Bridge service
using the net command. Enter net start vpnbridge to start the
service, and net stop vpnbridge to terminate the service.
| The PacketiX Server emulates the
service system of Windows NT or later when operating on an older
OS. There may be several limitations in this case, such as the
process terminating when the user logs off. |
Fig. 5-2-1 PacketiX VPN Bridge registered as a service |
Service Mode for UNIX Version PacketiX VPN Bridge
Please refer to 「7.3 Installing to Linux and Configuring the Default Settings」 for details on installing and launching the
Linux and other UNIX versions of the PacketiX VPN Bridge in Service
Mode.
5.2.2 User Mode
User Mode is a special type of operating mode. Operating the PacketiX
VPN Bridge in User Mode causes the PacketiX VPN Bridge to run in the
background as a user process. To operate the PacketiX VPN Bridge in User
Mode, it is necessary to log onto the system as a user and launch the
vpnbridge executable file each time the server is launched. Operations
may differ depending on the operating system as described below.
- Launching the VPN Bridge in User Mode on the Windows OS will
result in the server process running in the background only while
the user is logged on, and the process will terminate at the same
time that the user logs off.
- Meanwhile, launching the VPN Bridge in User Mode on a UNIX OS
will result in the VPN Bridge 's server process creating a child
process at that time, and running that in the background, thereby
enabling separation of the process from the user session.
Consequently, the VPN Bridge process will remain operational on the
OS even if the user logs off, and will continue running until the
system is shutdown or rebooted.
User Mode for Windows Version PacketiX VPN Bridge
To launch the Windows version VPN Bridge in User Mode, attach the
[/usermode] option to the vpnbridge .exe executable file and then
launch.
Once the launch is complete, an icon will appear in the task tray and
the VPN Bridge will have launched in User Mode. In this mode, the
VPN Bridge program operates as one which can be executed with general user
authority, similar to other application programs operating in User Mode
(such as Word, calculator and so on). That is why absolutely no System
Administrator authority is required to launch the VPN Bridge in User
Mode. However, the VPN Bridge process also terminates at the same time
that the user logs off. We recommend saving the above /usermode option
attached to the command line as a shortcut on the desktop or setting it
up in the [Startup] folder in order to facilitate the frequent launch of
the VPN Bridge in User Mode.
Fig. 5-2-2 PacketiX VPN Bridge launched in User Mode |
To terminate the User Mode once it has been launched, right click on
the icon in the task tray and select [Exit PacketiX VPN Bridge ].
Furthermore, clicking on [Hide task tray icon], hides the icon in the
task tray display. This function is available when the VPN Bridge is
launched regularly in User Mode and the icon display becomes a
hindrance. Note, however, that the VPN Bridge cannot be terminated from
the menu when the task tray icon is hidden. In this case, press the Ctrl
+ Alt + Del keys to open the Task Manager and end the vpnbridge .exe
process. When launching vpnbridge .exe the next time in User Mode, the
task tray icon can be restored by attaching the /usermode_showtray
option.
Fig. 5-2-3 Hide task tray icon menu |
| When using the PacketiX VPN Bridge ,
rather than operating the server by using System Administrator
authority and registering the server as a system service,
operating the server in User Mode with general user
authorization may enable security to be enhanced. Launching the
PacketiX VPN Bridge in User Mode may, however, result in the
inability to use the local bridge function. |
User Mode for Unix Version PacketiX VPN Bridge
To launch the VPN Bridge in User Mode on UNIX systems including
Linux, rather than registering the vpnbridge executable file in the
system as a daemon, attach the start argument from the command
line as shown below as if launching a normal application command (such
as ls, cat, etc.) and launch vpnbridge .
$ ./vpnbridge start
PacketiX VPN Bridge Service Started.
$
|
If control returns to the shell after the message [PacketiX VPN
Bridge Service Started.] is output, this means that the VPN Bridge was
properly launched in User Mode. To terminate the VPN Bridge once it has
been launched, attach the stop argument and launch the vpnbridge
as follows.
$ ./vpnbridge stop
PacketiX VPN Bridge Service Stopped.
$
|
When the VPN Bridge is launched on UNIX in User Mode, the process
operates and becomes a background process with that user's authority.
Therefore, the vpnbridge process continues to operate even if the user
logs out or disconnects the SSH connection. The process continues to
operate until the system is rebooted or until the process is forcibly
terminated by root.
As described in 「7.3 Installing to Linux and Configuring the Default Settings」, daemonizing and using the vpnbridge process in
UNIX operating systems is simply a matter of registering it so as to
instruct the operating system's startup script to call up vpnbridge
start. Even when running the VPN Bridge in Service Mode, something
equivalent to the procedure described here is automatically performed by
a system with root authority so there is fundamentally no difference.
Accordingly, the items described below also apply generally to the daemonized
VPN Bridge .
As shown below, the vpnbridge process is launched in two stages on
the UNIX version VPN Bridge . First, the first process named execsvc is
launched as a background process, after which that process creates a
child process using the fork() system call, and this child process
carries out the actual VPN processing. The parent process (process ID
1549 in the example below) constantly monitors the child process
(process ID 1550 in the example below) and in the event that an abnormal
error occurs, immediately terminates the process and launches it again
to attempt recovery (see 「3.3.12 Failure Recovery」 for details). The example below was
actually run on a particular Linux system so it may not appear the same
on different Linux or other operating systems. In addition, in order to
display multiple threads as multiple processes in the case of versions
with old Linux kernels (i.e. versions not compatible with native
threads), the actual vpnbridge processes created may be more than those
in the example below but this is a display issue and operation is in
fact normal.
$ ps auxf
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
neko 1549 0.0 0.8 5188 560 ? S< Nov24 0:00 /tmp/vpnbridge execsvc
neko 1550 0.0 4.0 11888 2520 ? S< Nov24 0:08 \_ /tmp/vpnbridge execsvc
|
Although it only occurs rarely, in the event that the VPN Bridge
process launched in User Mode goes out of control for some reason such
as a hardware malfunction (a memory shortage, for instance) and is
unable to be stopped by vpnbridge /stop, first forcibly terminate
the parent vpnbridge process (process ID 1549 in the example above) by
sending a signal to it using kill -KILL, then forcibly terminate
the remaining process (process ID 1550 in the above example) by sending
a signal to it with kill -KILL. Forcibly terminating the child
process first may cause the parent process to determine that the child
process terminated abnormally and launch it again. Depending on the
system, killall -KILL vpnbridge may enable the
simultaneous termination of all vpnbridge processes.
Moreover, when the vpnbridge receives the TERM signal (the
normal termination request signal), it performs termination processing
properly.
| The use of TCP/IP ports with a port
number less than 1024 in standby mode is not permitted for
processes operating with general user authority in the case of
UNIX operating systems. That is why TCP/IP listener ports with a
port number less than 1024 cannot be opened when operating the
PacketiX VPN Bridge in User Mode with general user authority
rather than operating it after registration as a system service
with System Administrator authority. Please note that although
the PacketiX VPN Bridge attempts to open the three ports 443,
992 and 8888 in default as listener ports, operating the server
in User Mode means that only the 8888 port goes into listen
mode. Additionally, launching the PacketiX VPN Bridge in User
Mode may result in inability to use the local bridge function. |
|