Terminal Emulation Using Secure Shell (SSH), Telnet, or TN3270
Secure Shell (SSH), Telnet, and TN 3270 are methods, or protocols, for connecting to host
computers and using them interactively. While you are connected to the host, your own computer simply acts as (emulates) a "dumb" terminal -- the processing happens on the remote host, not on your desktop.
At Penn, teminal emulation protocols are used to access many traditional
character (text) -based services housed on host computers. SSH is widely
used for host-based email (e.g., Mutt, Pine) and NetNews (e.g.,
slrn). Secure Telnet using Kerberos, introduced in January 2003, is available
on
many campus hosts as an alternative to SSH. (Note that Standard Telnet,
which sends unencrypted passwords across the network and is widely used
around the world, cannot be used to access Penn hosts that house critical
services (see Almanac for
details).) TN3270 emulation is required for the administrative systems housed
on IVY.UMIS.
"Pennified" terminal emulation software configured for the most widely used character-based resources on campus is available as part of the networking software suite
supported at Penn. Windows users may need to to install more than one terminal emulation package, depending on which systems they access.
Windows. The supported terminal emulators for Windows PCs are Host Explorer (for TN3270 and secure Telnet using Kerberos) and SecureCRT
(for SSH). Host Explorer configured for TN3270 emulation is required to
access the administrative systems housed on IVY.UMIS, but either HostExplorer or SecureCRT can be used for most other
text-based resources, such as e-mail and Netnews on pobox, mail.sas and other campus hosts.
Your Local Support Provider (LSP) can advise you on which package and protocol is recommended in your School or business unit. Recommendations can also be found in the document Email Specifications by School. Additional information and
download links for Host Explorer and SecureCRT can be found on their respective pages on the Supported Products site.
To connect to a Penn host using the Pennified version of SecureCRT or Host Explorer,
select the desired host from the "Connect" or "Sessions" menu. If the
host you wish to reach is not on the list, contact your LSP for assistance.
Macintosh. The supported terminal emulator for Macintosh is dataComet Secure, which supports SSH, secure Telnet using Kerberos,
and TN3270.
To connect to a host using the Pennified version of dataComet Secure, select
"Sessions" from the "File" menu and select the desired host from the
list. If the
host you wish to reach is not on the list, contact your LSP for assistance.
Additional information and
download links for dataComet-Secure can
be found on the supported products site.
Note: Many campus mail servers are configured to support both SSH terminal emulation and secure Telnet with Kerberos. You might prefer Telnet with Kerberos if you use another Kerberized service, such as Kerberized FTP. Telnet with Kerberos is strongly recommended if you delegate email to an assistant and have been sharing your password to allow the assistant to access your email account. Provided your assistant also uses a Kerberos-compliant email client, your account can be set up so both of you can log in to your account using your respective PennKeys and associated passwords rather than a shared password. Your LSP can help set this up.
Publicly accessible text-based services on the Internet, such as text-based library catalogs, generally use standard Telnet.
Some of these services may ask you to enter a public
password, which is usually specified on the access screen for the service.
Others require no password and immediately display the service's main
menu or require a few extra steps, such as prompting you to identify your
terminal type (vt100), before displaying the main menu. A service's help
screens, online directions, and navigational prompts should help you discover
your subsequent options. They should also tell you how to log off the
service when you have completed your search.
Related resources
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