Computer Home Network » Virtual Private Network

Virtual Private Network and ISP Connection

admin — Wed, 23 Dec 2009 08:19:30 +0000

VPN Broadband Access (Cable and DSL)

What Is Broadband?

Broadband technologies provide high-speed access to the Internet. These technologies are an alternative to dial-up methods that use a traditional analog modem.

The major broadband technologies are:
Cable Modem Service
Digital Subscriber Line (DSL) Service

Cable modem services use the same coaxial cable or fiber optic line that brings cable television into your home. A cable modem connects users to the Internet by means of the cable company’s network. Because of its superior bandwidth capacity, cable modem delivers greatly enhanced speed to users.

DSL services provide a high-bandwidth connection over the same wires that provide your telephone service. Since DSL uses a different frequency than the phone service, you can use the same line to make phone calls while your PC is connected to the Internet.
With both of these broadband technologies, your PC is always connected to the Internet.

Should I Use Broadband?

The high-speed, “always-on” Internet access provided by broadband technologies offers obvious advantages. And broadband might particularly benefit you if:
You need to be connected to the network for many hours a day from a fixed location.
You have large downloads/uploads to process on a regular basis.
You are a virtual worker who cannot get a reliable phone connection with a decent speed.

However, there are number of issues to consider when deciding if broadband is right for you:

Availability Cable modem or DSL services are not available in all locations.

Cost Broadband access is generally more expense than dial-up service. Prices typically range from $40 to $80 monthly depending on your area, your provider, and the specific type of service you need.

Security With a cable modem or DSL line, your PC is always connected to the Internet with a persistent IP address. Since this makes you a potential target for hackers, your PC should be secured by a firewall.

Portability Cable modem and DSL services are not portable. For example, you do not take them with you when you travel. If you need to access your network while traveling, you might need a separate dial-up ISP.

Comparing Cable Modem and DSL

Which is better, Cable modem or DSL? There is no simple answer to this question as each technology has its advantages. Indeed, local availability of these technologies will often determine which service you choose.

The following compares the two technologies on some key characteristics.

Cable Modem

Requires a cable connection.
Generally faster speed than DSL, but throughput can vary.
Cost relative to DSL varies based on location.

DSL

Requires a telephone line connection.
Generally slower speed than cable, but provides a more constant throughput with lower latency.
Cost relative to cable varies based on location.

More About Cable Modem Service

Cable modem service can be a particularly attractive option if you already have cable TV service or if you use only cellular phone service at your home.

Finding Cable Modem Service Providers

To find out if cable modem service is available in your area, start by calling your local cable TV company. Be aware, however, that some areas have more than one cable TV company. One provider might offer cable modem service, while the other does not.

Installation Issues

Typically, you will need to deal with only one vendor (the cable company) when installing cable modem service.

Some providers require that a service technician come to your home to install the service and setup your computer with appropriate software. Other providers give you the option of installing the software and setting up the cable modem yourself.

In either event, you should be aware that:

Not all cable modems work with every service provider. Before you purchase a modem, check with your provider to see which modems they support.
Even if cable TV functions in your home, you might not be eligible for Internet cable access if the line quality of your coaxial cable is too weak.

If you decide to install the cable modem yourself, be sure to:

Ask your cable company what kind of splitter to use. (In many cases, the cable company will provide you with a splitter.) When purchasing a splitter, ensure that it provides EMI isolation, and that it has sufficient frequency range (approximately 5-1000 MHz). The range should be printed on the splitter.

Place only one splitter between the point where the cable TV line enters the house and the cable modem/PC. If you have multiple TVs, split the line between the first splitter and the TV—not the line between the splitter and the modem.

Do not use amplifiers in the line leading to your cable modem as they are likely to distort the cable modem signals.

More About DSL Service

DSL is provided in a variety of specific service types. Some examples include ADSL, IDSL and HDSL. Sometimes the generic abbreviation DSL is used to collectively represent the various types.
DSL is an “always on” direct connection to the Internet usually made through a router, bridge, or DSL modem.

Finding DSL Service Providers

A good place to check for DSL availability in your location is the broadbandreports.com web site. Go to the Find Service function and be sure to pre-qualify the area in which you live. This site can give you an idea of what vendors support your area, how far you are from the provider, what types of DSL and options are available and approximate prices.

You should be aware, however, that a provider might choose not to support an area due to issues other than distance. This can be the case even if you successfully pre-qualify your area for DSL service.
Also, not all providers are listed on this web site. Therefore, you might want to check the other links listed in this topic as well.

Installation Issues

Typically, you will need to deal with three vendors (the phone company, the DSL provider, and the ISP) when installing DSL service. Even if your phone company is serving all three roles, they are usually separate divisions and communications between them can sometimes get confusing. Generally, the ISP is the designated point of contact.

As previously stated, the DSL service typically shares the copper phone line that you already have installed in your home. However with some types of xDSL (such as some IDSL implementations) do not always offer concurrent phone services on the DSL line. You should check with the ISP or phone company providing the service. In any event, DSL service can be configured to run on its own separately installed line.

Your DSL provider will set up a time for the phone company to change or install the line for DSL support. Sometime after the phone company completes this task, the DSL provider will install and test the inside wiring and equipment. Then your ISP should contact you to setup the mail and other special requirements that you may have.

When installing DSL service, you should be aware that:

Your DSL provider might need an IP address supplied by your ISP to properly test the line. Be sure the required IP address is obtained prior to installation time.

DSL installations do not always go smoothly, and delays in installation are not uncommon.

Installation problems can sometimes only be resolved effectively by getting all the parties involved together (such as through a conference call).

By: Aaron Adams

Virtual Private Network and Dialup Connectivity Modem Strings

admin — Sat, 19 Dec 2009 01:59:54 +0000

What to do when your dialup has intermittent network connectivity?

Q u e s t i o n

What do you do if you reside in a rural area, and your are constantly having problems connecting; when the modem tries to connect, it appears to be retraining continuously and then it either connects at a poor connection rate, or fails to connect at all.

A n s w e r

Due to the location, it may be necessary to lower the speed you connect at, as your modem is unable to maintain the faster V90 speeds.

If you are running Windows 95/98/ME, just add the appropriate modem string from the list below.

To find out what type of modem you have installed, click on Start, Settings, Control Panel then Modems.
To add the Extra String to your modem, double click on My Computer, then Dial-up Networking (for Windows ME, Dial-up Networking is located in the Control Panel).

Right click on your Orcon connection, then left click on Properties.

Click on the Configure button lower-down, click on the Connection tab along the top, and then the Advanced button lower-down.

Type the appropriate string for your modem in the field for Extra String.

If you are running Windows 2000/XP, to find out what type of modem you have installed:
Double click on My Computer, then Control Panel.

Double click on the Phone and Modem options icon, then click on the Modems tab along the top.

Click on the Properties button lower-down, then click on the Advanced tab along the top.

Type the appropriate string for your modem in the field for Extra Initialization String.

Note: If you are unable to connect after adding the below extra string, then this is not the right string for you.

If you are using Windows 95 and 98, you will need to restart your computer after adding the extra string, or you will get Error 630 when trying to connect without restarting your computer.

Examples:

Rockwell/Conexant HCF/SoftK56 (Internal) modem

Add +MS=V34,1 to the extra string

Rockwell/Conexant External modem

Add +MS=11

Lucent Winmodem

Add s38=0-v90=0

For Further Details and More Sources Your VPN Doctor has the Cure!
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By: Aaron Adams

Essential Computer Network Security Best Practices

admin — Sat, 28 Nov 2009 01:38:03 +0000

Network security should encompass all aspects of a network from the desktop to the perimeter. A multifaceted and multilayered approach to network security for any organization or business provides the ideal protection coverage against internal and external threats. For small networks or even a single computer, a router with integrated firewall is usually sufficient. For larger networks a dedicated firewall at the network perimeter may be more appropriate. A good number of dedicated firewall appliances can also provide secure Virtual Private Network (VPN) connectivity. The most common feature provided by dedicated firewalls is their ability to inspect, block and report malicious network activity usually initiated from the internet. Firewalls that provide this functionality are often designated as an Intrusion Prevention System (IPS).

A content filtering device is a good complement to a dedicated firewall. These types of devices usually include the ability to monitor, filter, regulate and report on all web related traffic. They are usually installed transparently in line between an internal switch and router or firewall. All internet inbound and outbound traffic is then forced to pass through it. This type of installation is often referred to as “bridged mode.” Some content filtering devices can also be integrated with a network directory for individual, detailed monitoring of end user web related traffic. Microsoft Active Directory and Novell eDirectory are examples of directory services that can integrate with a good number of content filtering devices.

Desktops and servers should be protected by antivirus and anti spyware applications. There is a wide variety of enterprise level threat protection software available in today’s current marketplace from numerous vendors. The ideal threat protection software should include at a minimum, frequent if not daily virus definition updates, centralized management and reporting, active protection and the ability to guard against unknown threats.

Another aspect of the network that needs security related consideration is what the users are allowed to do on desktops and laptops. Management may want to evaluate and implement access and rights appropriate for their environment and the nature of the organization. Should users be allowed to install software on their own or should the use of removable devices be disabled company wide are examples of issues that should be addressed when defining security policies and procedures.

Lastly, physical security is also important when considering all security related aspects of the network. Servers should be secured and access regulated and documented. It is also best to make sure that backup media is secured whether stored on-site or off-site. In conclusion, a proactive effort in utilizing these network security best practices coupled with consistent monitoring, constant re-assessments and adaptive reconfiguration are all essential in ensuring the safety and protection of an organizations data, intellectual properties and physical assets.

By: Anthony C.

Virtual Private Network and Network Connections

admin — Fri, 06 Nov 2009 04:02:37 +0000

Network In information technology, a network is a series of points or nodes interconnected by communication paths. Networks can interconnect with other networks and contain subnetworks.

Local Area Network (LAN) A local area network (LAN) is a group of computers and associated devices that share a common communications line or wireless link. Typically, connected devices share the resources of a single processor or server within a small geographic area (for example, within an office building). Usually, the server has applications and data storage that are shared in common by multiple computer users. A local area network may serve as few as two or three users (for example, in a home network) or as many as thousands of users (for example, in an FDDI network). See also: WAN and MAN

Wide Area Network (WAN) A wide area network (WAN) is a geographically dispersed telecommunications network. The term distinguishes a broader telecommunication structure from a local area network (LAN). A wide area network may be privately owned or rented, but the term usually connotes the inclusion of public (shared user) networks. An intermediate form of network in terms of geography is a metropolitan area network (MAN).

Metropolitan Area Network (MAN) A metropolitan area network (MAN) is a network that interconnects users with computer resources in a geographic area or region larger than that covered by even a large local area network (LAN) but smaller than the area covered by a wide area network (WAN). The term is applied to the interconnection of networks in a city into a single larger network (which may then also offer efficient connection to a wide area network). It is also used to mean the interconnection of several local area networks by bridging them with backbone lines. The latter usage is also sometimes referred to as a campus network.

Network Backbone A backbone is a larger transmission line that carries data gathered from smaller lines that interconnect with it.

Nodes In a network, a node is a connection point, either a redistribution point or an end point for data transmissions. In general, a node has programmed or engineered capability to recognize and process or forward transmissions to other nodes.

For Further Details and More Sources Your VPN Doctor has the Cure!

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By: Aaron Adams

Virtual Private Network Frequently Asked Questions

admin — Fri, 23 Oct 2009 14:09:06 +0000

1. Why do I get disconnected after 4 hours of use?
You will get disconnected because of the limited number of ports and the fact that 90% of all users do not need to be connected more than 4 hours, all units have been set to a 4-hour time limit.
If you require more time, you should disconnect gracefully before the time limit and reconnect so that you do not loose your work.

2. Why not use an 800 number all the time?
Using an 800 number costs the corporation 5 cents a minute versus calling a local number when available that costs 5-7 cents one time charge to initiate the call with no per minute charges.

3. Do I have to be connected when Email comes in or to prepare Email?
No, Email is stored in your server until you need to access it.
The proper way to handle Email when working remotely is to make a connection periodically during the day pulling your mail down and then disconnecting.
You can prepare your Email in the offline mode.
When you make your next connection to process incoming mail all prepared mail can be sent at this time.

4. What about reconnection issues?
If you are running Windows 95, NT, 2000 or XP making reconnections should be as simple as clicking on the icon to reconnect.

5. How do I speed up my dial-in connection?
Only install the necessary protocols.
Usually IP is the only one needed unless you are accessing Novell Servers.
Never install NetBEUI.
A good practice, if only accessing Novell Servers occasionally, is to create two configurations, one with IP access only and one with both IP and IPX. Use the second configuration only when required.

6. Why can’t I see all of the NT units in the Network Neighborhood?
When you dial into the Network Access Gateway you are normally on a segment without a master browser, which is how units are displayed in the Network Neighborhood.
This does not mean that you cannot access the unit however.
If the unit you are trying to access is a member of the corporate WINS structure and you have configured your remote unit per the configuration instructions, WINS will automatically resolve the units IP address when you Map a drive in Explorer.
The key to this is to know the computer name and share name that you require before starting the process.

7. Why does my Dial-Up Networking fail to work after loading AOL?
AOL sometimes replaces the TCP/IP Winsock driver, causing your PC perform erratically or not at all.

Fix:

1. Delete all references to TCP/IP from the network neighborhood properties.

2. Reboot the system.

3. Add the Microsoft TCP/IP protocol back in.

This will automatically add TCP/IP to all adapters and you should be functional again.

8. Can I use Network Address Translation (NAT) to attach my home computers via VPN?
In general NAT is not supported by the IPSEC VPN client.
Routers such as the Linksys BEFSR11 and BEFSR41 do support VPN with a software workaround.
NAT implementations may be used if One-to-One NAT is used.

9. Why can’t I get higher speed on my 56K v.90 modem into some NAG sites?
A 56k v.90 modem is asymmetric by design, so download speed can be as much as 56k but upload speed will be only up to 33.6bps.
For 56k to work, there must be only one analogue to digital (A/D) conversion in your local phone loop.
Thus when modems at both ends are analogue, 56k speeds will never be achieved as most PSTN exchanges run digital routing.
Some NAG sites use analogue phone lines with Cisco and standard 56k modems, while most PCs dialing up use a similar modem.
Between both the modems, it limits the download speed to about 33.6kbps maximum.
At the same time, many users might experience lower connection speeds due to other reasons, such as more poor line quality.
These factors will also contribute to the quality and speed of the line.

10. When I load the Extranet Client on my PC and Winpoet is installed on my machine, it crashes or does not work properly.
There are known issues running Winpoet software on the PC with the Nortel Extranet (VPN) Client.
To repair your system, boot in safe mode and uninstall the Winpoet Software.
A simple solution is to have users install the Linksys BEFSR41 hardware router.
It has a firmware PPPOE connector, which eliminates Winpoet from the PC and provides the added benefit a NAT firewall for the user with the ability to hook up to three other PCs.
A second option is to find a PPPOE Client that does not interfere with VPN Clients.
If you have WINPOET, please check with your local ISP to confirm it will work with the Nortel VPN client.
If not, or if they are not sure, please do not install the new client, or ask your ISP to find an alternative PPPOE Client that does not interfere with the Nortel VPN Client.
If you decide to use Winpoet with the new Nortel VPN client, Nortel strongly recommends using Winpoet 6.0 or higher.
Earlier versions of the Winpoet software are known to cause conflicts with the Nortel VPN client.
If you have Winpoet on your PC and experience problems (i.e. with an earlier version prior to 6.0) the following 8 steps will safely uninstall the Winpoet Software from your pc and repair your system to boot properly.

1. Login to Safe Mode.

2. Login under Admin profile.

3. Go to Add/Remove programs and uninstall Extranet Client. Do NOT reboot at the prompt.

4. Check to see if Winpoet adapter is installed. If so remove it.

5. Go to device manager/network adapters. Right click Winpoet or Winport adapter. Uninstall.

6. Go to Admin Tools./Services and disable Winpoet-over-ethernet.

7. Reboot PC.

8. Reinstall the extranet VPN client.

An alternative solution is to install the Linksys BEFSR41 hardware router. It has a firmware PPPOE connector, which eliminates the need of Winpoet from the PC.

11. My ISP remains connected and I have no known problem with my Internet Service Provider. The problem is intermittent.
Check the version of your Contivity Extranet Access client.
You should be using the current release of the client, 4.65 or higher. You can view the most current version by clicking on Current Version.

12. I am having problems with my VPN connection.
Try isolating the problem by process of elimination.

1. Is your Internet connection to the public Internet working properly?

2. Do you have the most current version of the Contivity Extranet Access client?

3. Have you recently installed any new software or hardware?

4. Were any hardware or software changes made since your VPN connection was last working?

5. Have you scanned your computer for Viruses?

If you are still experiencing problems, try uninstalling or removing the following items.

1. Disable your firewall, anti-virus software and any other maintenance or Security programs installed.

Try to connect.

2. Remove your router from your configuration.

Connect your PC directly to your Internet connection.

This is accomplished by connecting the cable coming out of your DSL/Cable modem, directly into your network card or USB connector.

If successful, the problem might be your router’s setup or firmware.

Refer to your manufacturer’s website or documentation for troubleshooting your router or contact the Vendor directly for support.

You must upgrade your firmware.

Please beware even though you might have just recently purchased your router, it might have been packaged with an older version of the software.

3. Enable your router, firewall/internet security programs one at a time.

Cable/DSL users: If you have a dial-up modem installed on your PC, try to test using a dialup connection.

Either use dialup to an ISP and then use VPN or dialup directly into your Network.

13. The upgrade to release 4.6X of the VPN client failed.
Refer to the list below and see if any of this applies:

Windows XP Disable the XP firewall.

VPN Software Most VPN clients cannot co-exist on the same machine.

Windows ME Remove and Add TCP/IP protocol.

Brother Multifunction Printer You may not be running the current Brother software for your printer. Windows 2000. Users should download drivers/software from the Brother website at http://www.brother.com or contact Brother for support.

14. How can I remove and re-install TCP/IP Protocol?
Below are instructions on how to remove and add TCP/IP for Windows 2000. (Refer to your operating system’s help screens, web support and/or documentation for instructions, if you are not using Windows 2000.)
Please be sure, no matter which operating system you use, that you elect to restart when finished (as prompted) or restart between each process.
For Windows 2000 you must be logged on as an administrator or a member of the Administrators group in order to complete this procedure.

Remove TCP/IP

1. Open Network and Dial-up Connections, click Start, point to Settings, and then click Network and Dial-up Connections.

2. Right-click any network connection, and then click Properties.

3. On the General tab (for a local area connection) or the Networking tab (all other connections), click Internet Protocol (TCP/IP), and then click Uninstall.

4. In the Uninstall Internet Protocol (TCP/IP) dialog box, click Yes.

Install TCP/IP

5. Open Network and Dial-up Connections. (Click Start, point to Settings, and then click Network and Dial-up Connections.)

6. Right-click the network connection for which you want to install and enable TCP/IP, and then click Properties.

7. On the General tab (for a local area connection) or the Networking tab (all other connections), if Internet Protocol (TCP/IP) is not in the list of installed components, then do the following:

A. Click Install.

B. Click Protocol and then click Add.

C. In the Select Network Protocol dialog box, click Internet Protocol (TCP/IP), and then click OK.

D. Verify that the Internet Protocol (TCP/IP) check box is selected, and then click OK.

TCP/IP is installed as the default network protocol if network adapter hardware was detected during Windows 2000 Setup. You only need to follow these instructions if the TCP/IP default selection was overridden during Setup.

15. I am using Windows XP Home or Professional and am unable to get to certain websites or resource servers when connected using VPN.
There are some known issues when using the Contivity Nortel client 4.60 on a PC running Windows XP.
The older version of the Nortel client (version 3.70) will fix the problem; however, the ultimate goal is to upgrade to the current version.
Please do not reinstall version 3.7X as a fix.

16. My ISP provider requires the installation of WinPoET. Can I use it with the latest release of the client?
If you are using WinPoET, it must be version 6.0 or higher of WinPoET.
Check with your ISP and request v6.0 or higher of WinPoET.

17. After installing v8.0 of AOL, I’ve experienced problems with my connections to my Network.
Users may experience problems with Windows Outlook email.
You must create two separate profiles; one profile as a Remote Connection (POP3) account for your AOL Internet email and another profile for a local LAN connection to your corporate Network email.

Here’s how: to do

1. Go to Start, Control Panel, Mail, Services, Show Profiles and Add the second profile.

2. Make sure the button “Prompt for a profile to be used” under General tab of MS Outlook properties is selected.

3. Disable the ATWPKT2 driver. (The files ATKPKT2.SYS and ATKPKT2.VXD are located in the AOL directory under PROGRAM_FILESCOMMON_FILES.)

18. I’m Unable to obtain an IP address while “Hotelling”.
When working remotely from a Hotel (Hotelling), you must launch your Internet explorer first to try and obtain an IP address.
If you just launch VPN, you won’t have obtained an IP address, and VPN may fail.
Disable your firewall, as the hotel may recommend.

19. Why do I get No Domain Available when dialing my ISP?
On your Internet Service Providers (ISP) dial connection, right click the mouse and select the properties button.
Click on the Server Type tab and make sure that the “Log On To Network” box is unchecked, otherwise you will hang trying to log into the Network when trying to connect.

20. Why do I run so slowly when using my VPN connection?
On your Internet Service Providers (ISP) dial connection.
Right click the mouse & select the properties button.
Click on the Server Type tab and make sure that the NetBEUI and IPX/SPX boxes are unchecked; otherwise you will see delays while the system tries the unsupported protocols.
VPN only supports the TCP/IP protocol so checking these boxes will only slow you down.

21. Why can’t I access my NT resources when using VPN?
Windows 95 users should make sure that they have the “Log On To the Network Box” checked in the Extranet Client per the instructions for the Extranet Client Install to use NT resources such as Exchange and file shares.

22. Why do I seem to be running slowly through my VPN connection?
Try turning off the Software Compression option on your Internet Service Providers (ISP) dial connection as the VPN client has it’s own compression. Right click the mouse & select the properties button.
Click on the Server Type tab and uncheck the “Software Compression” setting.

23. Why can’t I get to my Novell Servers when using VPN?
VPN only supports the TCP/IP Protocol & most Novell Servers require that you use IPX/SPX to access them.
Work with your Novell Administrators to change to NT or use a Version of Novell that supports IP traffic.

24. Cannot VPN Web Servers on the Internet after Establishing a Contivity VPN Client Connection.

Cause:

This is normal and occurs as a result of having all network traffic passed through the corporate network.

Typically, firewalls and other security measures on the corporate network will limit your VPN to the Internet.

Action:

The Contivity VPN Switch administrator can set up a default route on the Switch to forward traffic to the Internet.

If this default route is not configured, you will need to disconnect the Contivity connection to web browse the Internet through your ISP connection.

25. Cannot VPN Network Shares After establishing a Contivity VPN Connection.

Causes:

1. WINS Server may not be configured for IPsec connections on the Contivity VPN Switch.

2. Your system may be setup for a different domain than the one on the remote network.

Actions:

For the first problem, validate that the Contivity VPN Client has been configured with a WINS Server.

1. Follow the steps outlined above under “Problems with Name Resolution using DNS Services” to run IPCONFIG at a Command Prompt on NT 4.0 and to run WINIPCFG on Windows 95.

2. Verify that a Primary WINS Server is listed under the section for the adapter named IPSecShm on NT 4.0 and on Windows 95.

3. Verify that a Primary WINS Server is listed in WINIPCFG for the Contivity VPN Client adapter.

4. If there is no Primary WINS Server listed, notify the Network Administrator that the Contivity VPN Switch may not be properly configured.

For the second problem, skip the initial domain logon when Windows 95 starts and select “Log on to the Remote Domain” under the Options menu of the Contivity VPN Client dialog box.

1. You will then be prompted to log onto the domain of the remote network after the Contivity VPN connection is made.

2. This is the recommended method for users with Docking Station configurations.
Alternatively on both NT 4.0 and Windows 95, change your workstation to be a member of a Workgroup instead of a Domain.

1. From the Start Menu select Settings then Control Panel.

2. In the Control Panel, double-click on the Icon labeled “Network”. The Network Control Panel applet will open. Select the Identification tab.

3. On Windows 95, the entries on the Identification page can be modified directly, while on NT 4.0 it is necessary to click the Change button to change the entries.

Change to use a Workgroup and verify that the “Computer name” does not match one that may be on the remote network.

4. The name for the Workgroup is not important, so enter anything. Click OK to save the changes and reboot the machine.

When accessing a resource on the remote Domain, if you are prompted for a username and password, you will need to have a Domain name precede your user ID.

For example, if your user ID is JoeS and you are accessing a machine on the remote Domain named CORP, you would enter your username as CORPJoeS.

26. When trying to load the VPN Client on a Dual Processor unit you get an error message.
The Nortel VPN Client currently does not support Dual Processor units.

27. When I set up my home network, I installed Microsoft Internet Connection Sharing (ICS) so that all of my systems can reach the Internet. Now my VPN client no longer works.
The reason for this is that the Microsoft ICS uses Network Address Translation (NAT) to get the Internet connection, and NAT, which may not support IPSec connections.
The only way around this currently, is to make the unit running the ICS be the one you run your VPN connection from. Any downstream unit will not be functional for VPN.

28. Can Cisco or other IPSEC VPN Client software exist on the same box with Nortel Extranet Access Client? Is this supported?
They cannot coexist, and it is not supported.
The two virtual adapters installed with each client will conflict with each other.
There is a utility on the new Cisco clients that will uninstall a Nortel client if found by the Cisco VPN Unity Client install program.
All other VPN Clients require manual removal of the Nortel client or any other client.

29. I am having problems with my VPN connection not already discussed.
Try isolating the problem by process of elimination.

1. Is your Internet connection to the public Internet working properly?

2. Do you have the most current version of the Contivity Extranet Access client?

3. Have you recently installed any new software or hardware?

4. Were any hardware or software changes made since your VPN connection was last working?

5. Have you scanned your computer for viruses?

If you are still experiencing problems, try uninstalling/removing the following items.

1. Disable your firewall, anti-virus software and any other maintenance or Security programs installed. Try to connect.

2. Remove your router (Linksys, D-link, Cisco, Netgear, etc.) from your configuration.

Connect your PC directly to your Internet connection.

This is accomplished by connecting the cable coming out of your DSL/Cable modem, directly into your network card or USB connector.

If successful, the problem might be your router’s setup or firmware.

Refer to your manufacturer’s website or documentation for troubleshooting your router or contact the Vendor directly for support.

You must upgrade your firmware.

Please beware even though you might have just recently purchased your router, it might have been packaged with an older version of the software.

3. Enable your router, firewall/internet security programs one at a time.

Cable/DSL users: If you have a dial-up modem installed on your PC, try to test using a dialup connection. Either use dialup to an ISP and then use VPN.

30. VPN Problems with Name Resolution using DNS services.

Cause 1:

A DNS server may not be configured for IPsec connections on the Contivity VPN Switch.

Action 1:

Validate that the Contivity VPN client has been configured with a DNS entry.

For NT 4.0, open a Command Prompt and enter IPCONFIG /ALL.

Verify that a DNS server entry is listed.

For Windows 95, from the Start menu on the taskbar, select Run and enter WINIPCFG.

Select “Contivity VPN Adapter” from the pull down list of Adapters, then click More Info.

Record the information displayed under DNS Server entry and verify it with the network administrator.

Cause 2:

The hostname being resolved has both a public and a private IP address. This is commonly referred to as a Split-Horizon DNS.

Action 2:

Open a Command Prompt and ping the host you are trying to reach with a fully-qualified hostname (for example, http://www.vpnclient.com).

If you receive a response, verify that the IP address returned on the first line (for example, www.vpnclient.com [207.78.33.329] is an IP address from the remote corporate network.

If it is not, notify your network administrator that the internal hostname should be modified so that it is not the same as the external hostname.

Cause 3:

The retail release (a.k.a. “release 1″) of Windows 95 contained a bug that prevented use of more than one DNS server. This problem was fixed in OS Release2.

Action 3:
If you are using a release of Windows earlier than Release 2 of Windows 95, then you need to upgrade.

31. I am having problems mapping drives using the latest VPN client.
This is a known issue due to Microsoft that can occur when using cached credentials behind a NAT firewall.
The problem will occur for some users, but not others.
It can occur regardless of the VPN client you are using.
Some users may only experience this problem after upgrading to a new VPN client, but restoring the old client does not necessarily fix the problem.
You may try uninstalling the VPN Client and then reinstalling.
For Further Details and More SourcesYour VPN Doctor has the Cure!
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By: Aaron Adams