VanDyke Software

Entunnel FAQ

Entunnel FAQ

Why is Entunnel no longer in development?

VanDyke Software has made the decision to focus our development efforts on SecureCRT®, SecureFX®, and VShell®. The port forwarding (tunneling) functionality that Entunnel provides can be found in SecureCRT, which also provides shell access and terminal emulation.

Technical support for Entunnel ended on February 28, 2007. No new versions of Entunnel are scheduled to be released.

Does Entunnel support SSH1?

Entunnel supports SSH2 port forwarding and remote forwarding. The SSH2 protocol is superior to SSH1, and most new development in the industry focuses on SSH2.

Does Entunnel support X11 forwarding?

Entunnel does not currently support X11 forwarding. Please consider using SecureCRT® for your X11 forwarding needs at this time.

Does Entunnel work with older SSH2 servers?

Entunnel should work with most older SSH2 servers. The one exception that we know about is with F-Secure/DataFellows 2.0.12 servers. These servers seem to have a problem with an SSH2 client that does not request a shell. This results in the SSH2 server disconnecting Entunnel.

Can Entunnel be exported outside of the United States?

Yes, in most cases. Entunnel is now available for export under U.S. Bureau of Industry and Security regulations governing strong encryption software. Import restrictions by other countries may also affect encryption software availability. For more information, please see our web page on Exporting Encryption Software.

What do the different colors (red, yellow, green) that the Entunnel tray icon turns mean?

The Entunnel tray icon can be three different colors:

Red — all sessions are disconnected
Yellow — at least one session is the in process of connecting or disconnecting
Green — all opened sessions are connected

Why do I receive an "Invalid key" message when entering my registration data?

There are several things that you need to be aware of when entering the license key into the "License Data Dialog". The Name, Company, Serial Number, and Expiration fields must be entered exactly as shown in the registration notice (case is important). For example, the Expiration field should be "Never" as opposed to "never".

The key is made up of the letters A to F and the digits 0 to 9, so make sure that no letter "O"s have been entered in place of a "0" digit. We recommend using CTRL+V to paste the data into the license dialog (you can usually use CTRL+C to copy). Also, after you have entered the data into the fields, make sure that no leading or trailing blanks are present.

If you still get the "Invalid key" message after entering the registration data, exit out of Entunnel™ and start over.

If this does not resolve the problem, please contact us.

How do I set up Entunnel to work with the Microsoft Proxy Server?

To pass through the Microsoft Proxy Server, the SSH protocol requires either the WinSock proxy client on your machine or the SOCKS proxy protocol to be installed on the server. Check with your system administrator for information about which of these two methods to use.

If you are using the WinSock proxy client, the proxy will appear transparent to you and no special Entunnel configuration is required. Make sure that Entunnel's firewall type on the Global Configuration/Firewall category is set to "None".

If the server has SOCKS installed, select the appropriate SOCKS firewall type. Enter the IP address of the Microsoft Proxy Server and the port that it is using (usually 1080).

How do I move my Entunnel sessions to a different machine?

The following steps describe how to migrate your Entunnel sessions to another machine.

  1. Install Entunnel on the new machine.
  2. Find the location of the session configuration folder on the old machine. To do this, start Entunnel and select "Global Options..." from Entunnel's menu. The configuration folder location will be displayed in the "Configuration folder" field.
  3. Copy the configuration folder and its contents to the new machine. Under Windows XP/2000, the default location is:
  4. C:\Documents and Settings\<user>\Application Data\

    Under Windows Me/98/NT/95, the default location is:
    C:\Program Files\Entunnel\Config

  5. Run Entunnel on the new machine. If Entunnel does not find the sessions, select "Global Options" from Entunnel's menu. Browse to the correct location of the configuration folder and save your settings. When you restart Entunnel, it should use the migrated sessions.

How do I modify port-forwarding filters in Entunnel?

Entunnel has filters that control who can connect to port forwards that have been set up in Entunnel. By default, only connections coming from the machine that Entunnel is running on can connect to the port forwards. These port-forward filters are not exposed in the user interface.

You can change the port-forward filters by following the steps below (make sure Entunnel is not running at all when you attempt this):

  1. Find the .ini file associated with the session that you want to modify. The .ini files are located in the Entunnel Config folder under the subfolder called Sessions. The Global Options dialog also displays the location of the Entunnel Config folder in the "Configuration folder" field.
  2. Open the .ini file in Notepad.
  3. Look for the following line:

    S:"Port Forward Filter"=allow,,0 deny,,0
  4. Modify the line to read as follows:

    S:"Port Forward Filter"=allow,,0
    allow,,0 deny,,0

    Alternately, you could modify the line to read as follows allowing any IP address to connect to the port forward:

    S:"Port Forward Filter"=allow,,0

Port forwarding no longer works after installing XP SP2.

If port forwarding specifications involve local loopback IP addresses other than, you may be running into a bug in Windows XP that was introduced with Service Pack 2. This bug prevents binding to any loopback address other than

This issue can be resolved by installing a fix available from Microsoft at the following location:

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