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PuTTY Documentation
Introduction
PuTTY
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A.1 Introduction
A.1.1 What is PuTTY?
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PuTTY User Manual
Introduction to PuTTY
What are SSH, Telnet and Rlogin?
How do SSH, Telnet and Rlogin differ?
Getting started with PuTTY
Starting a session
Verifying the host key (SSH only)
Logging in
After logging in
Logging out
Using PuTTY
During your session
Copying and pasting text
Scrolling the screen back
The System menu
The PuTTY Event Log
Special commands
Starting new sessions
Changing your session settings
Copy All to Clipboard
Clearing and resetting the terminal
Full screen mode
Creating a log file of your session
Altering your character set configuration
Using X11 forwarding in SSH
Using port forwarding in SSH
Making raw TCP connections
Connecting to a local serial line
The PuTTY command line
Starting a session from the command line
-cleanup
Standard command-line options
-load: load a saved session
Selecting a protocol: -ssh, -telnet, -rlogin, -raw -serial
-v: increase verbosity
-l: specify a login name
-L, -R and -D: set up port forwardings
-m: read a remote command or script from a file
-P: specify a port number
-pw: specify a password
-agent and -noagent: control use of Pageant for authentication
-A and -a: control agent forwarding
-X and -x: control X11 forwarding
-t and -T: control pseudo-terminal allocation
-N: suppress starting a shell or command
-nc: make a remote network connection in place of a remote shell or command
-C: enable compression
-1 and -2: specify an SSH protocol version
-4 and -6: specify an Internet protocol version
-i: specify an SSH private key
-loghost: specify a logical host name
-hostkey: manually specify an expected host key
-pgpfp: display PGP key fingerprints
-sercfg: specify serial port configuration
-sessionlog, -sshlog, -sshrawlog: specify session logging
-proxycmd: specify a local proxy command
-restrict-acl: restrict the Windows process ACL
Configuring PuTTY
The Session panel
The host name section
Loading and storing saved sessions
Close Window on Exit
The Logging panel
Log file name
What to do if the log file already exists
Flush log file frequently
Options specific to SSH packet logging
Omit known password fields
Omit session data
The Terminal panel
Auto wrap mode initially on
DEC Origin Mode initially on
Implicit CR in every LF
Implicit LF in every CR
Use background colour to erase screen
Enable blinking text
Answerback to ^E
Local echo
Local line editing
Remote-controlled printing
The Keyboard panel
Changing the action of the Backspace key
Changing the action of the Home and End keys
Changing the action of the function keys and keypad
Controlling Application Cursor Keys mode
Controlling Application Keypad mode
Using NetHack keypad mode
Enabling a DEC-like Compose key
Control-Alt is different from AltGr
The Bell panel
Set the style of bell
Taskbar/caption indication on bell
Control the bell overload behaviour
The Features panel
Disabling application keypad and cursor keys
Disabling xterm-style mouse reporting
Disabling remote terminal resizing
Disabling switching to the alternate screen
Disabling remote window title changing
Response to remote window title querying
Disabling remote scrollback clearing
Disabling destructive backspace
Disabling remote character set configuration
Disabling Arabic text shaping
Disabling bidirectional text display
The Window panel
Setting the size of the PuTTY window
What to do when the window is resized
Controlling scrollback
Push erased text into scrollback
The Appearance panel
Controlling the appearance of the cursor
Controlling the font used in the terminal window
Hide mouse pointer when typing in window
Controlling the window border
The Behaviour panel
Controlling the window title
Warn before closing window
Window closes on ALT-F4
System menu appears on ALT-Space
System menu appears on Alt alone
Ensure window is always on top
Full screen on Alt-Enter
The Translation panel
Controlling character set translation
Treat CJK ambiguous characters as wide
Caps Lock acts as Cyrillic switch
Controlling display of line-drawing characters
Controlling copy and paste of line drawing characters
The Selection panel
Pasting in Rich Text Format
Changing the actions of the mouse buttons
Shift overrides application's use of mouse
Default selection mode
Configuring word-by-word selection
The Colours panel
Allow terminal to specify ANSI colours
Allow terminal to use xterm 256-colour mode
Indicate bolded text by changing...
Attempt to use logical palettes
Use system colours
Adjusting the colours in the terminal window
The Connection panel
Using keepalives to prevent disconnection
Disable Nagle's algorithm
Enable TCP keepalives
Internet protocol
Logical name of remote host
The Data panel
Auto-login username
Use of system username
Terminal-type string
Terminal speeds
Setting environment variables on the server
The Proxy panel
Setting the proxy type
Excluding parts of the network from proxying
Name resolution when using a proxy
Username and password
Specifying the Telnet or Local proxy command
Controlling proxy logging
The Telnet panel
Handling of OLD_ENVIRON ambiguity
Passive and active Telnet negotiation modes
Keyboard sends Telnet special commands
Return key sends Telnet New Line instead of ^M
The Rlogin panel
Local username
The SSH panel
Executing a specific command on the server
Don't start a shell or command at all
Enable compression
SSH protocol version
Sharing an SSH connection between PuTTY tools
The Kex panel
Key exchange algorithm selection
Repeat key exchange
The Host Keys panel
Host key type selection
Manually configuring host keys
The Cipher panel
The Auth panel
Display pre-authentication banner
Bypass authentication entirely
Attempt authentication using Pageant
Attempt TIS or CryptoCard authentication
Attempt keyboard-interactive authentication
Allow agent forwarding
Allow attempted changes of username in SSH-2
Private key file for authentication
The GSSAPI panel
Allow GSSAPI credential delegation
Preference order for GSSAPI libraries
The TTY panel
Don't allocate a pseudo-terminal
Sending terminal modes
The X11 panel
Remote X11 authentication
X authority file for local display
The Tunnels panel
Controlling the visibility of forwarded ports
Selecting Internet protocol version for forwarded ports
The Bugs and More Bugs panels
Chokes on SSH-1 ignore messages
Refuses all SSH-1 password camouflage
Chokes on SSH-1 RSA authentication
Chokes on SSH-2 ignore messages
Chokes on PuTTY's SSH-2 winadj requests
Miscomputes SSH-2 HMAC keys
Miscomputes SSH-2 encryption keys
Requires padding on SSH-2 RSA signatures
Misuses the session ID in SSH-2 PK auth
Handles SSH-2 key re-exchange badly
Ignores SSH-2 maximum packet size
Replies to requests on closed channels
Only supports pre-RFC4419 SSH-2 DH GEX
The Serial panel
Selecting a serial line to connect to
Selecting the speed of your serial line
Selecting the number of data bits
Selecting the number of stop bits
Selecting the serial parity checking scheme
Selecting the serial flow control scheme
Storing configuration in a file
Using PSCP to transfer files securely
Starting PSCP
PSCP Usage
The basics
user
host
source
target
Options
-ls list remote files
-p preserve file attributes
-q quiet, don't show statistics
-r copies directories recursively
-batch avoid interactive prompts
-sftp, -scp force use of particular protocol
Return value
Using public key authentication with PSCP
Using PSFTP to transfer files securely
Starting PSFTP
-b: specify a file containing batch commands
-bc: display batch commands as they are run
-be: continue batch processing on errors
-batch: avoid interactive prompts
Running PSFTP
General quoting rules for PSFTP commands
Wildcards in PSFTP
The open command: start a session
The quit command: end your session
The close command: close your connection
The help command: get quick online help
The cd and pwd commands: changing the remote working directory
The lcd and lpwd commands: changing the local working directory
The get command: fetch a file from the server
The put command: send a file to the server
The mget and mput commands: fetch or send multiple files
The reget and reput commands: resuming file transfers
The dir command: list remote files
The chmod command: change permissions on remote files
The del command: delete remote files
The mkdir command: create remote directories
The rmdir command: remove remote directories
The mv command: move and rename remote files
The ! command: run a local Windows command
Using public key authentication with PSFTP
Using the command-line connection tool Plink
Starting Plink
Using Plink
Using Plink for interactive logins
Using Plink for automated connections
Plink command line options
-batch: disable all interactive prompts
-s: remote command is SSH subsystem
-shareexists: test for connection-sharing upstream
Using Plink in batch files and scripts
Using Plink with CVS
Using Plink with WinCVS
Using public keys for SSH authentication
Public key authentication - an introduction
Using PuTTYgen, the PuTTY key generator
Generating a new key
Selecting the type of key
Selecting the size (strength) of the key
The Generate button
The Key fingerprint box
Setting a comment for your key
Setting a passphrase for your key
Saving your private key to a disk file
Saving your public key to a disk file
Public key for pasting into authorized_keys file
Reloading a private key
Dealing with private keys in other formats
Getting ready for public key authentication
Using Pageant for authentication
Getting started with Pageant
The Pageant main window
The key list box
The Add Key button
The Remove Key button
The Pageant command line
Making Pageant automatically load keys on startup
Making Pageant run another program
Using agent forwarding
Security considerations
Common error messages
The server's host key is not cached in the registry
WARNING - POTENTIAL SECURITY BREACH!
SSH protocol version 2 required by our configuration but server only provides (old, insecure) SSH-1
The first cipher supported by the server is ... below the configured warning threshold
Server sent disconnect message type 2 (protocol error): "Too many authentication failures for root"
Out of memory
Internal error, Internal fault, Assertion failed
Unable to use this private key file, Couldn't load private key, Key is of wrong type
Server refused our public key or Key refused
Access denied, Authentication refused
No supported authentication methods available
Incorrect CRC received on packet or Incorrect MAC received on packet
Incoming packet was garbled on decryption
PuTTY X11 proxy: various errors
Network error: Software caused connection abort
Network error: Connection reset by peer
Network error: Connection refused
Network error: Connection timed out
Network error: Cannot assign requested address
PuTTY FAQ
Introduction
What is PuTTY?
Features supported in PuTTY
Does PuTTY support SSH-2?
Does PuTTY support reading OpenSSH or ssh.com SSH-2 private key files?
Does PuTTY support SSH-1?
Does PuTTY support local echo?
Does PuTTY support storing settings, so I don't have to change them every time?
Does PuTTY support storing its settings in a disk file?
Does PuTTY support full-screen mode, like a DOS box?
Does PuTTY have the ability to remember my password so I don't have to type it every time?
Is there an option to turn off the annoying host key prompts?
Will you write an SSH server for the PuTTY suite, to go with the client?
Can PSCP or PSFTP transfer files in ASCII mode?
Ports to other operating systems
What ports of PuTTY exist?
Is there a port to Unix?
What's the point of the Unix port? Unix has OpenSSH.
Will there be a port to Windows CE or PocketPC?
Is there a port to Windows 3.1?
Will there be a port to the Mac?
Will there be a port to EPOC?
Will there be a port to the iPhone?
Embedding PuTTY in other programs
Is the SSH or Telnet code available as a DLL?
Is the SSH or Telnet code available as a Visual Basic component?
How can I use PuTTY to make an SSH connection from within another program?
Details of PuTTY's operation
What terminal type does PuTTY use?
Where does PuTTY store its data?
HOWTO questions
What login name / password should I use?
What commands can I type into my PuTTY terminal window?
How can I make PuTTY start up maximised?
How can I create a Windows shortcut to start a particular saved session directly?
How can I start an SSH session straight from the command line?
How do I copy and paste between PuTTY and other Windows applications?
How do I use all PuTTY's features (public keys, proxying, cipher selection, etc.) in PSCP, PSFTP and Plink?
How do I use PSCP.EXE? When I double-click it gives me a command prompt window which then closes instantly.
How do I use PSCP to copy a file whose name has spaces in?
Should I run the 32-bit or the 64-bit version?
Troubleshooting
Why do I see Fatal: Protocol error: Expected control record in PSCP?
I clicked on a colour in the Colours panel, and the colour didn't change in my terminal.
After trying to establish an SSH-2 connection, PuTTY says Out of memory and dies.
When attempting a file transfer, either PSCP or PSFTP says Out of memory and dies.
PSFTP transfers files much slower than PSCP.
When I run full-colour applications, I see areas of black space where colour ought to be, or vice versa.
When I change some terminal settings, nothing happens.
My PuTTY sessions unexpectedly close after they are idle for a while.
PuTTY's network connections time out too quickly when network connectivity is temporarily lost.
When I cat a binary file, I get PuTTYPuTTYPuTTY on my command line.
When I cat a binary file, my window title changes to a nonsense string.
My keyboard stops working once PuTTY displays the password prompt.
One or more function keys don't do what I expected in a server-side application.
Why do I see Couldn't load private key from ...? Why can PuTTYgen load my key but not PuTTY?
When I'm connected to a Red Hat Linux 8.0 system, some characters don't display properly.
Since I upgraded to PuTTY 0.54, the scrollback has stopped working when I run screen.
Since I upgraded Windows XP to Service Pack 2, I can't use addresses like 127.0.0.2.
PSFTP commands seem to be missing a directory separator (slash).
Do you want to hear about Software caused connection abort?
My SSH-2 session locks up for a few seconds every so often.
PuTTY fails to start up. Windows claims that the application configuration is incorrect.
When I put 32-bit PuTTY in C:\WINDOWS\SYSTEM32 on my 64-bit Windows system, Duplicate Session doesn't work.
Security questions
Is it safe for me to download PuTTY and use it on a public PC?
What does PuTTY leave on a system? How can I clean up after it?
How come PuTTY now supports DSA, when the website used to say how insecure it was?
Couldn't Pageant use VirtualLock() to stop private keys being written to disk?
Administrative questions
Would you like me to register you a nicer domain name?
Would you like free web hosting for the PuTTY web site?
Would you link to my web site from the PuTTY web site?
Why don't you move PuTTY to SourceForge?
Why can't I subscribe to the putty-bugs mailing list?
If putty-bugs isn't a general-subscription mailing list, what is?
How can I donate to PuTTY development?
Can I have permission to put PuTTY on a cover disk / distribute it with other software / etc?
Can you sign an agreement indemnifying us against security problems in PuTTY?
Can you sign this form granting us permission to use/distribute PuTTY?
Can you write us a formal notice of permission to use PuTTY?
Can you sign anything for us?
If you won't sign anything, can you give us some sort of assurance that you won't make PuTTY closed-source in future?
Can you provide us with export control information / FIPS certification for PuTTY?
As one of our existing software vendors, can you just fill in this questionnaire for us?
The sha1sums / sha256sums / etc files on your download page don't match the binaries.
Miscellaneous questions
Is PuTTY a port of OpenSSH, or based on OpenSSH or OpenSSL?
Where can I buy silly putty?
What does PuTTY mean?
How do I pronounce PuTTY?
Feedback and bug reporting
General guidelines
Sending large attachments
Other places to ask for help
Reporting bugs
Reporting security vulnerabilities
Requesting extra features
Requesting features that have already been requested
Support requests
Web server administration
Asking permission for things
Mirroring the PuTTY web site
Praise and compliments
E-mail address
PuTTY Licence
PuTTY hacking guide
Cross-OS portability
Multiple backends treated equally
Multiple sessions per process on some platforms
C, not C++
Security-conscious coding
Independence of specific compiler
Small code size
Single-threaded code
Keystrokes sent to the server wherever possible
640×480 friendliness in configuration panels
Automatically generated Makefiles
Coroutines in ssh.c
Single compilation of each source file
Do as we say, not as we do
PuTTY download keys and signatures
Public keys
Security details
The Development Snapshots key
The Releases key
The Secure Contact Key
The Master Keys
Key rollover
SSH-2 names specified for PuTTY
Connection protocol channel request names
Key exchange method names
Encryption algorithm names
Get in touch
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