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Supported Product

databeast Inc.'s dataComet-Secure is the recommended text-based network access client for OS X. dataComet-Secure supports Kerberized Telnet, TN3270, SSH1, and SSH2.

This version of dataComet-Secure has been configured to include profiles for many of the University's text-based servers. It contains the secure profiles necessary to connect to the University's mainframe applications (SRS, SFS, PR) on

Important note: BEN Application users should refer to the BEN Desktop Standards document for information about text-based network access clients that have been approved for use with BEN.


OS X compatibility

dataComet-Secure version 10.2.2 and above functions correctly in OS X Mountain Lion and later.


dataComet-Secure is site licensed at Penn and is available free of charge to members of the Penn community. dataComet-Secure is available for download using your PennKey and password.


This version of dataComet-Secure has been configured to include profiles for many of the University's mail servers.

This product needs further configuration for Kerberos. See these configuration instructions.

Related resources


About dataComet: dataComet allows Macintosh computers to access remote services on the Internet using the Telnet protocol. This protocol allows your computer to interact with a remote host as if it were a terminal directly attached to that host. Using the Internet's Telnet utility, however, requires that you know which host you want to log onto. In most instances, you will probably obtain the name of the host or its IP address from an Internet resource, from a book, or from some other published source. (Each host has an IP address. IP addresses uniquely identify each computer on the network.)

dataComet allows you to save your Telnet connections as icons to your desktop. Then, each time you want to connect to a particular host, you can double-click its saved Telnet icon. This is a quick way to start a session with those remote hosts that you want to connect to regularly. For directions on how to save a Telnet session, see "Saving a Telnet configuration."

Note: Network software is upgraded frequently.  The version you are using may work somewhat differently.

For more information about dataComet configuration, commands, and features, refer to the vendor's documentation.

Establishing a connection to a remote host

To establish a connection to a remote host:

  1. Double-click the dataComet icon to start the application.
  2. Select "New" from the File menu. Type the name of the session, as you want to remember it, in the Window name field.
  3. Type the name or IP address of the host in the Host Name/Address field.
  4. If the host requires a user name, type it in the Username field.
  5. dataComet tries to select an appropriate terminal type using its default Automatic setting. The host may require you to identify another terminal type. If so, select one from the list provided.
  6. Click "OK" to establish the connection.
  7. When the host's menu appears, follow the on-screen directions to navigate through the system.

Saving a Telnet configuration

You can save Telnet configurations for hosts that you want to connect to regularly. This allows you to begin a Telnet session quickly -- just double-click the saved dataComet icon -- without having to specify the host name, window name, and session characteristics each time you connect to the host.

To save a Telnet configuration:

  1. Follow steps 1 to 6 in "Establishing a Connection."
  2. Choose how you want to display characteristics for the session. Select the "Control" menu, and specify the following session characteristics:
    • Screen Size (usually 24 rows x 80 columns, on the "Emulator" menu)
    • Key Mapping (on the "Emulator" menu)
    • Font
    • Size (of font)
    • Color
  3. Select "Save configuration" from the File menu. A directory dialog box appears with the prompt to name the session.
  4. Type a name for the session in the Save configuration in field, and click "Save" to save the current settings. Save the Telnet session to your desktop or a folder of your choice.
  5. To access a saved configuration, double-click your dataComet icon.

Running multiple connections

You can establish multiple connections to a single host or to several different hosts concurrently. When you have more than one Telnet connection, it's a good idea to name each session. dataComet will display each session name in the title bar. To switch between active sessions, click the session window or select the session name from the Window menu. Remember to log off each host before quitting dataComet.

Closing a connection to a remote host

Each host should tell you how to log off the service when you have completed your work. The log-off directions usually appear on the menu when you first log on. At the host's prompt, type the command to quit the system.

If no log-off command was provided, type logout at the host's prompt or select "Close" from the File menu. If you have not previously saved a configuration for this host, a message asking "Save new document for ___?" appears. If you wish to save a configuration, click "Save" and follow the directions in "Saving a Telnet Configuration" above.

Quitting dataComet

After you have finished using a remote host, make sure you log off the host, then quit dataComet.

To quit dataComet, select "Quit" from the File menu.

Example: Establishing a Telnet session to use public Lynx services

Follow these steps to log onto a University of Kansas site that offers public Lynx access to the K.U. World Wide Web site as well as other services via Telnet.

  1.     Double-click the dataComet icon.
  2.     Select "New" from the File menu.
  3.     Type in the Host Name/Address field.
  4.     Click "OK" to establish the connection.
  5.     At the login screen, follow the directions on the screen to connect to the desired service.
  6.     To quit, type q at the prompt, then press "y".
  7.     To quit dataComet, select "Quit" from the File menu.

Check for secure Administrative mainframe sessions

Beginning February 3, 2015, encrypted (secure) connections to the Administrative mainframe are required. Follow the steps below to determine if your connection is secure.

  1. Establish a connection to the Administrative mainframe.
  2. Inspect the lower left corner of the connection window (last line on the dataComet session window).
  3. If the small padlock icon is present, your session is encrypted and secure. No further action is required.
  4. If there is no padlock icon showing, your session is not secure. Select one of the options below (A) or (B) to ensure your Administrative mainframe session profiles are encrypted and secure.

(A) Install a recent dataComet-Secure version

Download and install a recent version of dataComet-Secure. It contains secure profiles for popular Administrative mainframe sessions (such as SRS, SFS, and PR).

(B) Reconfigure an existing profile for 3270 SSL-enabled telnet

Change the configurations for your existing profile as indicated in the steps below. Ensure that you are using a recent version of dataComet-Secure.

  1. Launch dataComet-Secure from your Applications folder (Go → Applications → dataComet-Secure).
  2. From the File menu, select Sessions, then select the profile you want to change.
  3. From the Window menu, select Reconfigure Session...
  4. Under the Session Type section, click the Telnet radio button and click the Initiate SSL/TLS check box.
  5. Click Configure… that’s right across from the Telnet radio button. The Telnet configuration: window appears.
  6. Under SSL/TLS version, click the Allow any root certificate check box, then click OK.
  7. In the Port field, type 992
  8. Click OK again to open your Telnet session.
  9. From the File menu, select Save Configuration...
  10. When the dialog box to save the session configuration appears, choose the directory in which to save the reconfigured Telnet profile, then click Save.
  11. When the replace file prompt displays, click Replace. The specified profile is now reconfigured for SSL-enabled Telnet.