PuTTY is a terminal emulator supporting Telnet and SSH protocols. It has flexible configuration options allowing compatibility with most legacy operating systems and environments.
Quote from the PuTTY web site:
"PuTTY is a free implementation of Telnet and SSH for Win32 and Unix platforms, along with an xterm terminal emulator."
PuTTY supports a variety of customizations allowing the display to be configured to the user's personal taste. This includes:
- Screen size (number of rows and columns) including full-screen mode
- Font size
- Background and font color for standard and bolded text, along with programmed ANSI color support
- Sound created for bell character
Other features supported include:
- Output logging
- Scroll-back buffer
- Printer support
- PSFTP utility - a PuTTY implementation of SFTP
PuTTY provides 5 basic communication protocols.
- Raw - simple terminal communication without the telnet negotiation of features and detecting of terminal type
- Telnet - standard Telnet protocol used for terminal communication with most systems. All data on the network is in plain-text which could be viewed by anyone with a network sniffer between the PC and the target server.
- Rlogin - execution of single commands and displaying the results.
- SSH - an encrypted implementation of communication similar to Telnet. All communication cannot be viewed while on the network. PuTTY includes support for:
- Authentication methods
- Keyboard-interactive - username and password verified by SYSUAF
- Pageant - SSH key exchange
- Tunneling including X11 forwarding
- Authentication methods
- Serial - user specified COM port and communication parameters
If the Telnet connection is going through a firewall that drops idle connections, a communication parameter may be set to send keepalive messages regularly to prevent the connection from being dropped.
Due to the diferences between the DEC VT series keyboards and the standard, and some not-so-standard, PC keyboards, terminal emulators must choose how to map many of the function and editing keys. By default, the backspace key is mapped to the DEC delete key.
The 6 editing keys on the VT series keyboards are:
These keys are mapped to standard PC keyboard for these keys is:
There are two common mappings for these keys. For users who have memorized the placement of the DEC VT keyboard editing keys, mapping these keys based on key placement may be easiest to use. This maps the PC keys to the DEC VT keys as:
- Insert -> Find
- Home -> Insert
- Page Up -> Remove
- Delete -> Select
- End -> Previous
- Page Down -> Next
When the user is not so familiar with the placement of the DEC VT keys, or when using a laptop or other keyboard which may not have these keys with the standard placement, mapping these keys based on function usually works best. This maps the PC keys to the DEC VT keys as:
- Insert -> Insert
- Home -> Find
- Page Up -> Previous
- Delete -> Remove
- End -> Select
- Page Down -> Next
PuTTY provides six pre-configured keyboard mappings.
Provides good emulation of VT style keyboard on PCs with numeric keypad. The "Num Lock" key maps to PF1 (or Gold key) on the VT keyboard. The "/", "*", and "-" keys map to PF2, PF3 and PF4. The editing keys are mapped based on function.
"Num Lock", "/", "*" and "-" on the keypad are mapped to the PF1-PF4 keys on the DEC VT keyboard. The editing keys are mapped based on function. In numeric mode, the keypad keys have different definitions depending on the state of the "Num Lock" key.
- Xterm R6
Provides good emulation of VT style keyboard on laptop computers without a numeric keypad. The F1-F4 keys are mapped to PF1-PF4. The editing keys are mapped based on function.
Provides good emulation of VT style keyboard on PCs with numeric keypad. The "Num Lock" key maps to PF1 (or Gold key) on the VT keyboard. The "/", "*", and "-" keys map to PF2, PF3 and PF4. The editing keys are mapped based on placement.
F1-F4 keys are mapped to PF1-PF4. The remaining function keys are generally not used. The editing keys are mapped based on function.
The "Num Lock", "/", "*" and "-" keys are not mapped. The F4-F7 keys are mapped to PF1-PF4. The editing keys are mapped based on function.
Function keys F1-F12 are mapped to the DEC VT function keys F1-F12. Shift F1 - shift F10 on the PC keyboard are mapped to the DEC VT function keys F11-F20.