the telnet locker

CONTENTS:

Kerberos-authenticated telnet client and server, binaries and source for Unix. NCSA telnet for Mac is not in this locker, but is available at MIT via anonymous FTP from net-dist.mit.edu.

DESCRIPTION:

This locker contains versions of telnet and telnetd that take advantage of Kerberos authentication and DES encryption. They interoperate with other versions of telnet and telnetd, but when the new telnet connects to the new telnetd, you get automatic passing of some environment variables, including DISPLAY (properly translated from :0.0 to hostname:0.0 if necessary). Window size changes are handled appropriately.

HOW TO RUN:

• For authentication and encryption,

  add telnet; ktelnet -ax host

  On non-Athena workstations, use the kinit program first.
• For the same functionality but better mnemonics, Athena has added the equivalent,

  add telnet; ktelnet -safe host

• To run the telnet server on your Unix workstation at MIT,
  1. Send mail to accounts@mit.edu giving the name of your machine and asking for a rcmd srvtab.
  2. If your workstation is running Athena release 7.7 or higher (type /bin/athena/machtype -A to find out), run mkserv remote as root and skip the following three steps.
  3. If /etc/athena/telnetd does not exist on your workstation, copy it from the telnet locker.
  4. If /etc/athena/krb.conf and /etc/athena/krb.realms don't exist on your workstation, copy them from any Athena workstation or dialup server.
  5. If it is not an Athena workstation but some homedirs are in AFS, make a symlink /bin/athena/attach to /bin/true.
  6. Find the line in /etc/athena/inetd.conf or /etc/inetd.conf that starts with ``telnet'' and change the last two columns to ``/etc/athena/telnetd telnetd'' for login without a password, or to ``/etc/athena/telnetd telnetd -a off'' for behavior like the Athena dialup servers, i.e. ask for password in addition to Kerberos authentication.
  7. Wait for a reply to your request for a srvtab.
  8. Install your srvtab.

INTERFACES:

TTY only

VERSIONS:

• for Alpha/OSF/1: telnet '94 with Athena extensions
• for DECstation/Ultrix: telnet '94 with Athena extensions
• for linux: telnet '94 with Athena extensions
• for RS6000/AIX: telnet '94 with Athena extensions
• for HP9000/HP-UX: telnet '94
• for Vax/BSD: telnet '92

DEPENDENCIES:

Kerberos authentication and encryption will not work without the files /etc/athena/krb.conf and /etc/athena/krb.realms. You will also need Kerberos utilities: kinit, klist, kdestroy

DATAFILES:

telnet does not use datafiles

LICENSE SERVER:

no

SUPPORT ISSUES --

I/S SUPPORT:

CONSULTING:

supported

TRAINING:

no minicourse is devoted to telnet

DOCUMENTATION:

• telnet man page
• telnetd man page
• "Two Telnet Scenarios" documents the rationale behind telnetd's behavior on Athena dialup servers.
• "Coming to closure on athena.dialup.mit.edu" talks about load-balancing issues.
• The zmodem/kermit issue
• Tech articles:
  • Loopholes Loom Large in MITnet (April 22, 1994)
  • Jeff Schiller and Joanne Costello's response letter (April 29, 1994)
  • How to Be Secure on MITnet (April 22, 1994)
  • IS Works to Address Security of MITnet (September 27, 1994)
  • Intruders Breach Network Security; Passwords Stolen (January 11, 1995)
  • MITnet extends to dorms, ILGs; poses security risk (February 7, 1995)
  • IS Discovers Packet Sniffer in Building 20 (March 24, 1995)