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This chapter contains information to help you resolve problems installing or running the VPN Client. It also contains notes helpful to writing programs for special needs.
This section describes how to perform the following tasks:
If you are having problems running the VPN Client on your PC, you can gather system information that is helpful to a customer support representative and e-mail it to us. We recommend that you do the following before you contact us.
Go to the Start menu and select Programs > Accessories > System Tools > System Information.
Windows displays the Microsoft System Information screen, such as the one in Figure 5-1.
Select a category and the screen displays details for that category. You can then execute the Export command and choose a name and destination. Windows creates a text file, which you can attach to an e-mail message and send to the support center.
On the NT or Win2K operating system, you can run a utility named WINMSD from a command-line prompt. WINMSD generates a file containing information about your system configuration, and the software and drivers installed.
To use this utility, perform the following steps:
This action displays a window with a DOS prompt, such as c:\.
Step 2 Type the following command at the DOS prompt:
C:\>winmsd /a /f
where /a = all and /f = write to file.
This command generates a text (.txt) file with the name of your computer and places the file in the directory from which you run the command. For example, if the name of your machine is SILVER and you execute the command from the c: drive (as shown above), the text file name is silver.txt.
If you open the file with a text editor, such as Notepad, you see a file such as the one shown in
Figure 5-2, which was from a Windows NT system.
You can attach this file to an e-mail message and send it to the support center.
This section describes some common problems and what to do about them.
You may experience a problem with your Windows 98 system shutting down when the VPN Client software is installed. If so, you need to disable the fast shutdown feature, as follows:
Step 2 From the General page, select the Advanced button.
Step 3 Choose the Disable Fast Shutdown option.
Some versions of Internet Explorer silently control startup options in Windows 95 so that every time you start your system, Dial-Up Networking launches. If this occurs, as it does in Internet Explorer 3.0, go to View > Options > Connections and uncheck the option Connect to the Internet as needed.
The Set MTU option is used primarily for troubleshooting connectivity problems.
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Note The VPN Client automatically adjusts the MTU size to suit your environment, so running this application should not be necessary. |
MTU sizing affects fragmentation of IPSec and IPSec through NAT mode packets to your connection destination. A large size (for example, over 1400) can increase fragmentation. Using 1400 or smaller usually prevents fragmentation. Fragmentation and reassembly of packets at the destination causes slower tunnel performance. Also, many firewalls do not let fragments through.
To change the size of the MTU, use the following procedure:
The Set MTU window appears.
Step 2 Click a network adapter on the list of network adapters.
Step 3 Click one of the following choices under MTU Options:
Default | The factory setting for this adapter type. |
576 (in bytes) | The standard size for dial-up adapters. |
1400 (in bytes) | The choice recommended for both straight IPSec and IPSec through NAT. Using this value guarantees that the client does not fragment packets under normal circumstances. |
Custom | Enter a value in the box. The minimum value for MTU size is 68 bytes. |
Step 4 Click OK.
You must restart your system for your change to take effect
This section contains information to aid a programmer in writing programs that perform routine tasks.
As part of a program, you might want to test a connection to see if it is active before performing the tasks that are the purpose of the program. To test the connection, you can poll the TunnelEstablished entry in the HKEY_LOCAL_MACHINE registry. To see this entry, bring up the Registry Editor and go to SOFTWARE > Cisco Systems > VPN Client. (See Figure 5-4.) In the list of entries, you see TunnelEstablished. This entry can have only two values: 1 or 0. If the connection is working, the value is 1; if not, the value is 0.
Posted: Mon Feb 11 13:56:04 PST 2002
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