\A{faq} PuTTY \i{FAQ}

This FAQ is published on the PuTTY web site, and also provided as an
appendix in the manual.

\H{faq-intro} Introduction

\S{faq-what}{Question} What is PuTTY?

PuTTY is a client program for the SSH network protocol, usually used
to run terminal sessions over a network. It also supports running
terminal sessions over a serial port, and a variety of older legacy
network protocols such as Telnet, Rlogin, and SUPDUP.

These protocols are all used to run a remote session on a computer,
over a network. PuTTY implements the client end of that session: the
end at which the session is displayed, rather than the end at which
it runs.

In really simple terms: you run PuTTY on a Windows machine, and tell
it to connect to (for example) a Unix machine. PuTTY opens a window.
Then, anything you type into that window is sent straight to the
Unix machine, and everything the Unix machine sends back is
displayed in the window. So you can work on the Unix machine as if
you were sitting at its console, while actually sitting somewhere
else.

\S{faq-why}{Question} Why use PuTTY when I could use OpenSSH?

These days, Windows comes with a version of OpenSSH as an optional
component of the operating system, and its command prompt windows are
much more like Unix terminals than they used to be. So it's true that
if you want SSH on Windows, you can use OpenSSH in a Windows terminal,
and not have to install PuTTY at all.

We're not going to try to persuade you that you \e{shouldn't} use
OpenSSH in preference to PuTTY. PuTTY is free software, in the \q{no
cost} sense as well as the \q{freedom} sense \dash we don't get more
money by having more users. PuTTY and OpenSSH have different feature
sets, and different ways of doing things, and it's entirely up to you
which you prefer.

A few examples of things you might like about PuTTY:

\b a range of built-in options to log your session to a file

\b a range of configurable tweaks to the terminal emulation

\b a unified saved-session system that lets you customise your
settings for a particular destination host, including the SSH-specific
settings (like authentication) \e{and} terminal and logging setup

\b access to mid-session configuration via the GUI, instead of
stealing a key sequence from your remote terminal session. With the
OpenSSH [Return][\cw{~}][thing] system, you always have to remember
it's there even when you're not using it, to avoid triggering it with
input you meant to send to the server. In PuTTY, the corresponding
facilities (like reconfiguring port forwardings) are done using the
GUI menus, and \e{all} keystrokes typed into the window consistently
go to the server.

\b simply, \e{different} terminal emulation from Windows's one, which
you might find works better for some remote applications. Or you might
not, of course; it will depend on what kind of machine you're
connecting to, and maybe your personal preferences. And many people
will have no opinion either way.

\b and, of course, support for things that aren't SSH. In particular,
talking to serial ports instead of the network.

But if none of this impresses you, and you'd rather use Windows's
version of OpenSSH, that's up to you.

Unix, of course, has always had OpenSSH, even before the Unix version
of PuTTY existed. So this question has been relevant for much longer!
When we first wrote the Unix port of PuTTY, people asked us why it was
necessary. Partly the answer was that having the PuTTY code run on
Unix too made it easier to develop in general (Unix had a wider range
of better development and debugging facilities, and in my opinion,
still does). But the same considerations as above also apply: on Unix
too I use GUI PuTTY for my SSH connections, so that I never have to
deal with that \cw{~} business, and I use the Unix \cw{pterm} for my
local terminal sessions too.

\H{faq-support} Features supported in PuTTY

\I{supported features}In general, if you want to know if PuTTY supports
a particular feature, you should look for it on the
\W{https://www.chiark.greenend.org.uk/~sgtatham/putty/}{PuTTY web site}.
In particular:

\b try the
\W{https://www.chiark.greenend.org.uk/~sgtatham/putty/changes.html}{changes
page}, and see if you can find the feature on there. If a feature is
listed there, it's been implemented. If it's listed as a change made
\e{since} the latest version, it should be available in the
development snapshots, in which case testing will be very welcome.

\b try the
\W{https://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/}{Wishlist
page}, and see if you can find the feature there. If it's on there,
and not in the \q{Recently fixed} section, it probably \e{hasn't} been
implemented.

\S{faq-disksettings}{Question} Does PuTTY support storing its
settings in a disk file?

Not at present, although \k{config-file} in the documentation gives
a method of achieving the same effect.

\S{faq-password-remember}{Question} Does PuTTY have the ability to
\i{remember my password} so I don't have to type it every time?

No, it doesn't.

Remembering your password is a bad plan for obvious security
reasons: anyone who gains access to your machine while you're away
from your desk can find out the remembered password, and use it,
abuse it or change it.

In addition, it's not even \e{possible} for PuTTY to automatically
send your password in a Telnet session, because Telnet doesn't give
the client software any indication of which part of the login
process is the password prompt. PuTTY would have to guess, by
looking for words like \q{password} in the session data; and if your
login program is written in something other than English, this won't
work.

In SSH, remembering your password would be possible in theory, but
there doesn't seem to be much point since SSH supports public key
authentication, which is more flexible and more secure. See
\k{pubkey} in the documentation for a full discussion of public key
authentication.

\S{faq-hostkeys}{Question} Is there an option to turn off the
\I{verifying the host key}annoying host key prompts?

No, there isn't. And there won't be. Even if you write it yourself
and send us the patch, we won't accept it.

Those annoying host key prompts are the \e{whole point} of SSH.
Without them, all the cryptographic technology SSH uses to secure
your session is doing nothing more than making an attacker's job
slightly harder; instead of sitting between you and the server with
a packet sniffer, the attacker must actually subvert a router and
start modifying the packets going back and forth. But that's not all
that much harder than just sniffing; and without host key checking,
it will go completely undetected by client or server.

Host key checking is your guarantee that the encryption you put on
your data at the client end is the \e{same} encryption taken off the
data at the server end; it's your guarantee that it hasn't been
removed and replaced somewhere on the way. Host key checking makes
the attacker's job \e{astronomically} hard, compared to packet
sniffing, and even compared to subverting a router. Instead of
applying a little intelligence and keeping an eye on oss-security, the
attacker must now perform a brute-force attack against at least one
military-strength cipher. That insignificant host key prompt really
does make \e{that} much difference.

If you're having a specific problem with host key checking \dash perhaps
you want an automated batch job to make use of PSCP or Plink, and the
interactive host key prompt is hanging the batch process \dash then the
right way to fix it is to add the correct host key to the Registry in
advance, or if the Registry is not available, to use the \cw{\-hostkey}
command-line option (see \k{using-cmdline-hostkey}). That way, you
retain the \e{important} feature of host key checking: the right key
will be accepted and the wrong ones will not. Adding an option to turn
host key checking off completely is the wrong solution and we will not
do it.

If you have host keys available in the common \i\c{known_hosts} format,
we have a script called
\W{https://git.tartarus.org/?p=simon/putty.git;a=blob;f=contrib/kh2reg.py;hb=HEAD}\c{kh2reg.py}
to convert them to a Windows .REG file, which can be installed ahead of
time by double-clicking or using \c{REGEDIT}.

If you just manage and connect to a lot of servers with different host
keys, you could consider using a \q{certification authority}, so that
you only have to configure PuTTY once on each client machine to accept
host keys from any of your servers in future. See \k{config-ssh-kex-cert}.

\S{faq-server}{Question} Will you write an SSH server for the PuTTY
suite, to go with the client?

Not one that you'd want to use.

While much of the protocol and networking code can be made common
between a client and server, to make a \e{useful} general-purpose
server requires all sorts of fiddly new code like interacting with OS
authentication databases and the like.

A special-purpose SSH server (called \i{Uppity}) can now be built from
the PuTTY source code. But it's not usable as a general-purpose
server. Its purpose is to be a test harness.

If someone else wants to use this as a basis for writing a
general-purpose SSH server, they'd be perfectly welcome to, of course.
But they would have to take responsibility for all of the security
hardening that hasn't been done; we don't have time for that, and we
don't have motivation. The code is available if anyone else wants to
try it.

\H{faq-ports} Ports to other operating systems

PuTTY is best known as a Windows tool, but it has an internal
abstraction layer that permits it to run on other systems too. Here we
discuss current, past and future possible ports.

\S{faq-ports-general}{Question} What ports of PuTTY exist?

Currently, release versions of PuTTY tools only run on Windows systems
and Unix. The Windows version is provided in the form of executables,
for both x86 and Arm based Windows systems. The Unix version is
provided as source code (although at least some Linux distributions
provide it pre-built).

Our standard Windows executable builds aim to run on all versions of
Windows still in security support. Earlier versions might be supported
if it's easy, but we don't promise to test them reliably. (For
example, PuTTY 0.83 still runs on Windows XP \dash but the previous
release 0.82 didn't.)

We do not have release-quality ports for any other systems at the
present time. If anyone told you we had an Android port, or an iOS
port, or any other port of PuTTY, they were mistaken. We don't.

There are some third-party ports to various platforms, mentioned
on the
\W{https://www.chiark.greenend.org.uk/~sgtatham/putty/links.html}{Links page of our website}.

\S{faq-mac-port}{Question} Will there ever be a \I{Mac OS}Mac version of PuTTY?

As of 2026, I doubt that the core PuTTY team will ever finish one.

We've tried more than once. Around 2005 we attempted one in the form
of a native Cocoa application, but it turned out to be very slow to
redraw its window for some reason we never got to the bottom of.

In 2015, after porting the GTK front end to work with GTK 3, we began
another attempt, based on making small changes to the GTK code and
building it against the OS X Quartz version of GTK 3. This didn't have
the speed issue, and came much closer to being finished. But
unfortunately the Quartz GTK port seems to have bit-rotted: the last
time I tried to build the Mac port, I couldn't even figure out how to
install a GTK it would build with.

If anyone were interested in picking this up and finishing it, the
TODO list in \c{unix/main-gtk-application.c} in the source code is a
good place to start, and I'd be happy to provide advice and
discussion.

\S{faq-iphone}{Question} Is there a version of PuTTY for mobile operating systems?

We don't have one ourselves, for either Android or iOS.

The last time we checked, there was a third-party SSH client for the
iPhone and iPod\_Touch called
\W{http://www.instantcocoa.com/products/pTerm/}{pTerm}, which is
apparently based on PuTTY. (This is nothing to do with our
similarly-named \c{pterm}, which is a standalone terminal emulator.)

We don't know of any Android SSH application based on the PuTTY code.
(There are Android SSH applications based on other implementations.)

\H{faq-embedding} Embedding PuTTY in other programs

\S{faq-dll}{Question} Is the SSH or Telnet code available as a DLL?

No, it isn't. It would take a reasonable amount of rewriting for
this to be possible, and since the PuTTY project itself doesn't
believe in DLLs (they make installation more error-prone) none of us
has taken the time to do it.

Most of the code cleanup work would be a good thing to happen in
general, so if anyone feels like helping, we wouldn't say no.

See also
\W{https://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/dll-frontend.html}{the wishlist entry}.

\S{faq-ipc}{Question} How can I use PuTTY to make an SSH connection
from within another program?

Probably your best bet is to use Plink, the command-line connection
tool. If you can start Plink as a second Windows process, and
arrange for your primary process to be able to send data to the
Plink process, and receive data from it, through pipes, then you
should be able to make SSH connections from your program.

\H{faq-details} Details of PuTTY's operation

\S{faq-term}{Question} What \i{terminal type} does PuTTY use?

By default, PuTTY has always announced its terminal type to SSH (and
Telnet) servers as \c{xterm}, and tried to behave close enough to
\c{xterm} itself that this works well enough.

PuTTY also supports some terminal \i{control sequences} not supported by
the real \cw{xterm}: notably the Linux console sequences that
reconfigure the colour palette, and the title bar control sequences
used by \i\cw{DECterm} (which are different from the \cw{xterm} ones;
PuTTY supports both).

Since PuTTY was new, the \c{xterm} terminal type has split into many
subtypes, so you may find that you benefit from upgrading to a
terminal type such as \c{xterm-256color} to enable more features.

In modern versions of Linux, the terminal type database also includes
a terminal type for PuTTY itself, so you could try setting the
terminal type to \cq{putty}! We didn't write that database entry, and
don't know in detail what it includes or which version of PuTTY it was
based on.

(We are sometimes asked why PuTTY doesn't use the \cq{putty} terminal
type as default. Part of the reason is inertia. Another is that all
the world's not Linux: I still worry that some servers will be
confused by that terminal type. But perhaps one day we should switch
over.)

\S{faq-settings}{Question} Where does PuTTY store its data?

On Windows, PuTTY stores most of its data (saved sessions, SSH host
keys) in the \i{Registry}. The precise location is

\c HKEY_CURRENT_USER\Software\SimonTatham\PuTTY

and within that area, saved sessions are stored under \c{Sessions}
while host keys are stored under \c{SshHostKeys}.

PuTTY also requires a random number seed file, to improve the
unpredictability of randomly chosen data needed as part of the SSH
cryptography. This is stored by default in a file called \i\c{PUTTY.RND};
this is stored by default in the \q{Application Data} directory,
or failing that, one of a number of fallback locations. If you
want to change the location of the random number seed file, you can
put your chosen pathname in the Registry, at

\c HKEY_CURRENT_USER\Software\SimonTatham\PuTTY\RandSeedFile

You can ask PuTTY to delete all this data; see \k{faq-cleanup}.

On Unix, PuTTY stores all of this data in a directory \cw{~/.putty}
by default.

\S{faq-trust-sigils} Why do small \i{PuTTY icon}s appear next to the login
prompts?

As of PuTTY 0.71, some lines of text in the terminal window are marked
with a small copy of the PuTTY icon (as far as pixels allow).

This is to show trustworthiness. When the PuTTY icon appears next to a
line of text, it indicates that that line of text was generated by
PuTTY itself, and not generated by the server and sent to PuTTY.

Text that comes from the server does not have this icon, and we've
arranged that the server should not be able to fake it. (There's no
control sequence the server can send which will make PuTTY draw its
own icon, and if the server tries to move the cursor back up to a line
that \e{already} has an icon and overwrite the text, the icon will
disappear.)

This lets you tell the difference between (for example) a legitimate
prompt in which PuTTY itself asks you for your private key passphrase,
and a fake prompt in which the server tries to send the identical text
to trick you into telling \e{it} your private key passphrase.

\S{faq-plink-pause} Why has Plink started saying \q{Press Return to
begin session}?

As of PuTTY 0.71, if you use Plink for an interactive SSH session,
then after the login phase has finished, it will present a final
interactive prompt saying \q{Access granted. Press Return to begin
session}.

This is another defence against servers trying to mimic the real
authentication prompts after the session has started. When you pass
through that prompt, you know that everything after it is generated by
the server and not by Plink itself, so any request for your private
key passphrase should be treated with suspicion.

In Plink, we can't use the defence described in \k{faq-trust-sigils}:
Plink is running \e{in} the terminal, so anything it can write into
the terminal, the server could write in the same way after the session
starts. And we can't just print a separator line without a pause,
because then the server could simply move the cursor back up to it and
overwrite it (probably with a brief flicker, but you might easily miss
that). The only robust defence anyone has come up with involves this
pause.

If you trust your server not to be abusive, you can turn this off. It
will also not appear in various other circumstances where Plink can be
confident it isn't necessary. See \k{plink-option-antispoof} for
details.

\H{faq-howto} HOWTO questions

\S{faq-login}{Question} What login name / password should I use?

This is not a question you should be asking \e{us}.

PuTTY is a communications tool, for making connections to other
computers. We maintain the tool; we \e{don't} administer any computers
that you're likely to be able to use, in the same way that the people
who make web browsers aren't responsible for most of the content you can
view in them. \#{FIXME: less technical analogy?} We cannot help with
questions of this sort.

If you know the name of the computer you want to connect to, but don't
know what login name or password to use, you should talk to whoever
administers that computer. If you don't know who that is, see the next
question for some possible ways to find out.

\# FIXME: some people ask us to provide them with a login name
apparently as random members of the public rather than in the
belief that we run a server belonging to an organisation they already
have some relationship with. Not sure what to say to such people.

\S{faq-commands}{Question} \I{commands on the server}What commands
can I type into my PuTTY terminal window?

Again, this is not a question you should be asking \e{us}. You need
to read the manuals, or ask the administrator, of \e{the computer
you have connected to}.

PuTTY does not process the commands you type into it. It's only a
communications tool. It makes a connection to another computer; it
passes the commands you type to that other computer; and it passes
the other computer's responses back to you. Therefore, the precise
range of commands you can use will not depend on PuTTY, but on what
kind of computer you have connected to and what software is running
on it. The PuTTY team cannot help you with that.

(Think of PuTTY as being a bit like a telephone. If you phone
somebody up and you don't know what language to speak to make them
understand you, it isn't \e{the telephone company}'s job to find
that out for you. We just provide the means for you to get in touch;
making yourself understood is somebody else's problem.)

If you are unsure of where to start looking for the administrator of
your server, a good place to start might be to remember how you
found out the host name in the PuTTY configuration. If you were
given that host name by e-mail, for example, you could try asking
the person who sent you that e-mail. If your company's IT department
provided you with ready-made PuTTY saved sessions, then that IT
department can probably also tell you something about what commands
you can type during those sessions. But the PuTTY maintainer team
does not administer any server you are likely to be connecting to,
and cannot help you with questions of this type.

\S{faq-startmax}{Question} How can I make PuTTY start up \i{maximise}d?

There's no setting built in to PuTTY for this. But you can create a
Windows shortcut to start PuTTY from, and set it as \q{Run Maximized}.

\S{faq-startsess}{Question} How can I create a \i{Windows shortcut} to
start a particular saved session directly?

To run a PuTTY session saved under the name \q{\cw{mysession}},
create a Windows shortcut that invokes PuTTY with a command line
like

\c \path\name\to\putty.exe -load "mysession"

(Note: prior to 0.53, the syntax was \c{@session}. This is now
deprecated and may be removed at some point.)

\S{faq-startssh}{Question} How can I start an SSH session straight
from the command line?

Use the command line \c{putty \-ssh host.name}. Alternatively, create
a saved session that specifies the SSH protocol, and start the saved
session as shown in \k{faq-startsess}.

\S{faq-cutpaste}{Question} How do I \i{copy and paste} between PuTTY and
other Windows applications?

By default, copy and paste works similarly to the X Window System. You
use the left mouse button to select text in the PuTTY window. The act
of selection \e{automatically} copies the text to the clipboard: there
is no need to press Ctrl-Ins or Ctrl-C or anything else. In fact,
pressing Ctrl-C will send a Ctrl-C character to the other end of your
connection (just like it does the rest of the time), which may have
unpleasant effects. The \e{only} thing you need to do, to copy text to
the clipboard, is to select it.

This default dates from the days when PuTTY was new, and its main
target audience was \q{Unix expatriates} \dash people who mostly used
Unix desktop systems and were used to the X copy/paste mechanism,
having to use Windows instead. The aim was \q{closest thing you can
get to an xterm on Windows}.

If you prefer a more \q{Windows native} interface for copy and paste,
via keystrokes or menu actions, with nothing happening automatically
on select, then you can reconfigure the behaviour flexibly in PuTTY's
configuration. See \k{config-selection} for details.

To paste the clipboard contents into a PuTTY window, by default you
click the right mouse button. If you have a three-button mouse and
are used to X applications, you can configure pasting to be done by
the middle button instead, but this is not the default because most
Windows users don't have a middle button at all.

You can also paste by pressing Shift-Ins.

\S{faq-options}{Question} How do I use all PuTTY's features (public
keys, proxying, cipher selection, etc.) in PSCP, PSFTP and Plink?

Most major features (e.g., public keys, port forwarding) are available
through command line options. See \k{using-general-opts}.

Not all features are accessible from the command line yet, although
we'd like to fix this. In the meantime, you can use most of
PuTTY's features if you create a PuTTY saved session, and then use
the name of the saved session on the command line in place of a
hostname. This works for PSCP, PSFTP and Plink (but don't expect
port forwarding in the file transfer applications!).

\S{faq-pscp}{Question} How do I use PSCP.EXE? When I double-click it
gives me a command prompt window which then closes instantly.

PSCP is a command-line application, not a GUI application. If you
run it without arguments, it will simply print a help message and
terminate.

To use PSCP properly, run it from a Command Prompt window. See
\k{pscp} in the documentation for more details.

\S{faq-pscp-spaces}{Question} \I{spaces in filenames}How do I use
PSCP to copy a file whose name has spaces in?

If PSCP is using the newer SFTP protocol (which is usual with most
modern servers), this is straightforward; all filenames with spaces
in are specified using a single pair of quotes in the obvious way:

\c pscp "local file" user@host:
\c pscp user@host:"remote file" .

However, if PSCP is using the older SCP protocol for some reason,
things are more confusing. If you're specifying a file at the local
end, you just use one set of quotes as you would normally do:

\c pscp "local filename with spaces" user@host:
\c pscp user@host:myfile "local filename with spaces"

But if the filename you're specifying is on the \e{remote} side, you
have to use backslashes and two sets of quotes:

\c pscp user@host:"\"remote filename with spaces\"" local_filename
\c pscp local_filename user@host:"\"remote filename with spaces\""

Worse still, in a remote-to-local copy you have to specify the local
file name explicitly, otherwise PSCP will complain that they don't
match (unless you specified the \c{\-unsafe} option). The following
command will give an error message:

\c c:\>pscp user@host:"\"oo er\"" .
\c warning: remote host tried to write to a file called 'oo er'
\c          when we requested a file called '"oo er"'.

Instead, you need to specify the local file name in full:

\c c:\>pscp user@host:"\"oo er\"" "oo er"

\H{faq-trouble} Troubleshooting

\S{faq-colours}{Question} I clicked on a colour in the \ii{Colours}
panel, and the colour didn't change in my terminal.

That isn't how you're supposed to use the Colours panel.

During the course of a session, PuTTY potentially uses \e{all} the
colours listed in the Colours panel. It's not a question of using
only one of them and you choosing which one; PuTTY will use them
\e{all}. The purpose of the Colours panel is to let you adjust the
appearance of all the colours. So to change the colour of the
cursor, for example, you would select \q{Cursor Colour}, press the
\q{Modify} button, and select a new colour from the dialog box that
appeared. Similarly, if you want your session to appear in green,
you should select \q{Default Foreground} and press \q{Modify}.
Clicking on \q{ANSI Green} won't turn your session green; it will
only allow you to adjust the \e{shade} of green used when PuTTY is
instructed by the server to display green text.

\S{faq-bce}{Question} When I run full-colour applications, I see
areas of black space where colour ought to be, or vice versa.

You almost certainly need to change the \q{Use \i{background colour} to
erase screen} setting in the Terminal panel. If there is too much
black space (the commoner situation), you should enable it, while if
there is too much colour, you should disable it. (See \k{config-erase}.)

\S{faq-idleout}{Question} My PuTTY sessions unexpectedly close after
they are \I{idle connections}idle for a while.

Some types of \i{firewall}, and almost any router doing Network Address
Translation (\i{NAT}, also known as IP masquerading), will forget about
a connection through them if the connection does nothing for too
long. This will cause the connection to be rudely cut off when
contact is resumed.

You can try to combat this by telling PuTTY to send \e{keepalives}:
packets of data which have no effect on the actual session, but
which reassure the router or firewall that the network connection is
still active and worth remembering about.

Keepalives don't solve everything, unfortunately; although they
cause greater robustness against this sort of router, they can also
cause a \e{loss} of robustness against network dropouts. See
\k{config-keepalive} in the documentation for more discussion of
this.

\S{faq-timeout}{Question} PuTTY's network connections time out too
quickly when \I{breaks in connectivity}network connectivity is
temporarily lost.

This is a Windows problem, not a PuTTY problem. The timeout value
can't be set on per application or per session basis. To increase
the TCP timeout globally, you need to tinker with the Registry.

On Windows 95, 98 or ME, the registry key you need to create or
change is

\c HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\
\c   MSTCP\MaxDataRetries

(it must be of type DWORD in Win95, or String in Win98/ME).
(See MS Knowledge Base article
\W{http://support.microsoft.com/default.aspx?scid=kb;en-us;158474}{158474}
for more information.)

On Windows NT, 2000, or XP, the registry key to create or change is

\c HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\
\c   Parameters\TcpMaxDataRetransmissions

and it must be of type DWORD.
(See MS Knowledge Base articles
\W{http://support.microsoft.com/default.aspx?scid=kb;en-us;120642}{120642}
and
\W{http://support.microsoft.com/default.aspx?scid=kb;en-us;314053}{314053}
for more information.)

Set the key's value to something like 10. This will cause Windows to
try harder to keep connections alive instead of abandoning them.

\S{faq-puttyputty}{Question} When I \cw{cat} a binary file, I get
\q{PuTTYPuTTYPuTTY} on my command line.

Don't do that, then.

This is designed behaviour; when PuTTY receives the character
Control-E from the remote server, it interprets it as a request to
identify itself, and so it sends back the string \q{\cw{PuTTY}} as
if that string had been entered at the keyboard. Control-E should
only be sent by programs that are prepared to deal with the
response. Writing a binary file to your terminal is likely to output
many Control-E characters, and cause this behaviour. Don't do it.
It's a bad plan.

To mitigate the effects, you could configure the answerback string
to be empty (see \k{config-answerback}); but writing binary files to
your terminal is likely to cause various other unpleasant behaviour,
so this is only a small remedy.

\S{faq-wintitle}{Question} When I \cw{cat} a binary file, my \i{window
title} changes to a nonsense string.

Don't do that, then.

It is designed behaviour that PuTTY should have the ability to
adjust the window title on instructions from the server. Normally
the control sequence that does this should only be sent
deliberately, by programs that know what they are doing and intend
to put meaningful text in the window title. Writing a binary file to
your terminal runs the risk of sending the same control sequence by
accident, and cause unexpected changes in the window title. Don't do
it.

\S{faq-password-fails}{Question} My \i{keyboard} stops working once
PuTTY displays the \i{password prompt}.

No, it doesn't. PuTTY just doesn't display the password you type, so
that someone looking at your screen can't see what it is.

Unlike the Windows login prompts, PuTTY doesn't display the password
as a row of asterisks either. This is so that someone looking at
your screen can't even tell how \e{long} your password is, which
might be valuable information.

\S{faq-keyboard}{Question} One or more \I{keyboard}\i{function keys}
don't do what I expected in a server-side application.

If you've already tried all the relevant options in the PuTTY
Keyboard panel, you may need to mail the PuTTY maintainers and ask.

It is \e{not} usually helpful just to tell us which application,
which server operating system, and which key isn't working; in order
to replicate the problem we would need to have a copy of every
operating system, and every application, that anyone has ever
complained about.

PuTTY responds to function key presses by sending a sequence of
control characters to the server. If a function key isn't doing what
you expect, it's likely that the character sequence your application
is expecting to receive is not the same as the one PuTTY is sending.
Therefore what we really need to know is \e{what} sequence the
application is expecting.

The simplest way to investigate this is to find some other terminal
environment, in which that function key \e{does} work; and then
investigate what sequence the function key is sending in that
situation. One reasonably easy way to do this on a \i{Unix} system is to
type the command \i\c{cat}, and then press the function key. This is
likely to produce output of the form \c{^[[11~}. You can also do
this in PuTTY, to find out what sequence the function key is
producing in that. Then you can mail the PuTTY maintainers and tell
us \q{I wanted the F1 key to send \c{^[[11~}, but instead it's
sending \c{^[OP}, can this be done?}, or something similar.

You should still read the
\W{https://www.chiark.greenend.org.uk/~sgtatham/putty/feedback.html}{Feedback
page} on the PuTTY website (also provided as \k{feedback} in the
manual), and follow the guidelines contained in that.

\S{faq-privkey-control-moved}{Question} Since 0.78, I can't find where
to configure my SSH private key.

In PuTTY 0.78, the \q{\ii{Private key} file for authentication} control,
where you specify a \c{.\i{PPK}} file for SSH public key authentication,
moved to a new \q{Credentials} panel in the configuration dialog. You can
find this by opening the \q{SSH} category in the tree view on the left,
then opening the \q{Auth} subcategory under that, then clicking on
\q{Credentials}. On this page you'll find the \q{Browse...} button you
need to select a \c{.PPK} file for authentication, as described in
\k{config-ssh-privkey}.

(This control had previously been on the \q{Auth} panel since public
key authentication was first released in 2002, so many online how-to
guides still describe it there. The configuration controls were
reorganised to make room for features added in 0.78, such as OpenSSH
certificates.)

\H{faq-secure} Security questions

\S{faq-publicpc}{Question} Is it safe for me to download PuTTY and
use it on a public PC?

It depends on whether you trust that PC. If you don't trust the
public PC, don't use PuTTY on it, and don't use any other software
you plan to type passwords into either. It might be watching your
keystrokes, or it might tamper with the PuTTY binary you download.
There is \e{no} program safe enough that you can run it on an
actively malicious PC and get away with typing passwords into it.

If you do trust the PC, then it's probably OK to use PuTTY on it
(but if you don't trust the network, then the PuTTY download might
be tampered with, so it would be better to carry PuTTY with you on a
USB stick).

\S{faq-cleanup}{Question} What does PuTTY leave on a system? How can
I \i{clean up} after it?

PuTTY will leave some Registry entries, and a random seed file, on
the PC (see \k{faq-settings}). Windows 7 and up also remember some
information about recently launched sessions for the \q{jump list}
feature.

If you are using PuTTY on a public PC, or somebody else's PC, you
might want to clean this information up when you leave. You can do
that automatically, by running the command \c{putty \-cleanup}. See
\k{using-cleanup} in the documentation for more detail. (Note that
this only removes settings for the currently logged-in user on
\i{multi-user systems}.)

If PuTTY was installed from the installer package, it will also
appear in \q{Add/Remove Programs}. Current versions of the installer
do not offer to remove the above-mentioned items, so if you want them
removed you should run \c{putty \-cleanup} before uninstalling.

\S{faq-virtuallock}{Question} Couldn't Pageant use
\cw{VirtualLock()} to stop private keys being written to disk?

Unfortunately not. The \cw{VirtualLock()} function in the Windows
API doesn't do a proper job: it may prevent small pieces of a
process's memory from being paged to disk while the process is
running, but it doesn't stop the process's memory as a whole from
being swapped completely out to disk when the process is long-term
inactive. And Pageant spends most of its time inactive.

\S{faq-windowsstore}{Question} Is the version of PuTTY in the
\i{Microsoft Store} legit?

The free-of-charge \q{PuTTY} application at
\W{https://apps.microsoft.com/store/detail/putty/XPFNZKSKLBP7RJ}{this link}
is published and maintained by us. The copy there is the latest
release, usually updated within a few days of us publishing it on our
own website.

There have been other copies of PuTTY on the store, some looking quite
similar, and some charging money. Those were uploaded by other people,
and we can't guarantee anything about them.

The first version we published to the Microsoft Store was 0.76 (some
time after its initial release on our website).

\H{faq-admin} Administrative questions

\S{faq-putty-org}{Question} Is \cw{putty.org} your website?

No, it isn't, and it never has been. We don't own it; we can't control
it; we have no responsibility for anything it does.

\cw{putty.org} was set up by an opportunist selling a competing SSH
client for money, who initially used it to interpose adverts for their
own commercial SSH implementation in the course of providing a link to
our free one. Then in July 2025 it changed its content to host
anti-vaccine propaganda. We have no idea what it might do next.

Since the start of PuTTY, the real PuTTY web site, run by the PuTTY
team, has always been at
\W{https://www.chiark.greenend.org.uk/~sgtatham/putty/}\cw{https://www.chiark.greenend.org.uk/~sgtatham/putty/}.

We don't recommend that anyone use \cw{putty.org} as a convenient
redirector, or indeed any \e{other} convenient landing page that is
not ours. There are a few others, some set up in entirely good faith,
but you never know.

As of August 2025, we have registered
\W{https://putty.software/}\cw{putty.software} and made that into an
\e{official} landing page. If you'd like a short easy URL, that's the
one to use, especially if we move the main website there in future.

\S{faq-putty-org-pivot}{Question} When \cw{putty.org} replaced its
content with anti-vaccine propaganda in July 2025, was that because
you were hacked or vandalised or taken over?

No, because \cw{putty.org} was never ours in the first place (see
\k{faq-putty-org}). It wasn't stolen from us, or bought from us. The
same person who owned it all along decided to change its content.

\S{faq-real-website}{Question} With all these landing pages and
imitators, how can I be sure where the \e{real} PuTTY website is?

Every release of PuTTY embeds a URL to the web site, via the \q{Visit
web site} button in the About box.

The real website is where \e{PuTTY itself} says it is.

If you download a cryptographically signed version of PuTTY \dash
either a Windows binary signed with Simon Tatham's Authenticode key,
or anything signed with the PuTTY team's GPG key \dash then you can
confirm that the URL embedded in that copy is the one that the
developers themselves endorse as the true web site.

As of August 2025, \W{https://putty.software/}\cw{putty.software} is a
second web location owned by us, the PuTTY developers. That too is
endorsed by signed copies of PuTTY, via being mentioned in this FAQ
section of the help file.

If we move the web site later \dash as of August 2025, our plan is to
move it from the chiark domain name to once the latter is generally
recognised as legitimate \dash then we will keep a redirection of some
kind at the old location, so that it continues to work. Both URLs will
continue to be legitimate places to find PuTTY, whichever is currently
preferred.

\S{faq-the}{Question} Why do the download links point to
\cw{the.earth.li} and not chiark? Has your website been hacked?

We haven't been hacked: links to \cw{the.earth.li} are legit. The
files for released versions of PuTTY are hosted on a different server
from the web pages, for bandwidth reasons.

The download site \cw{the.earth.li} is hosted by
\W{https://www.mythic-beasts.com/}{Mythic Beasts}, and we're very
grateful to them!

\S{faq-domain}{Question} Would you like me to register you a nicer
domain name?

No, thank you. We've got one: \W{https://putty.software/}\cw{putty.software}.

For a long time, this FAQ entry said that we were happy with the site
where it is. However, in 2025, as a result of some media attention to
\cw{putty.org}, it became clear that search engines these days seem to
prefer short whole domain names over user subdirectories on a larger
server.

So we registered a domain name ourselves. As of August 2025,
\W{https://putty.software/}\cw{putty.software} is a small landing
page, similar to third-party redirectors except not run by a third
party. After we've got the word out and built some trust, the plan is
to move the whole PuTTY site there and turn the old chiark site into a
redirection.

\S{faq-webhosting}{Question} Would you like free web hosting for the
PuTTY web site?

We already have some, thanks.

\S{faq-link}{Question} Would you link to my web site from the PuTTY
web site?

Only if the content of your web page is of definite direct interest
to PuTTY users. If your content is unrelated, or only tangentially
related, to PuTTY, then the link would simply be advertising for
you.

This is still true even if you offer to pay us. We aren't interested
in trading links for money, and we \e{certainly} aren't interested in
trading links for other links. If we don't want to link to you for
free, then we probably won't want to link to you at all.

If you have software based on PuTTY, or specifically designed to
interoperate with PuTTY, or in some other way of genuine interest to
PuTTY users, then we will probably be happy to add a link to you on
our Links page. And if you're running a particularly valuable mirror
of the PuTTY web site, we might be interested in linking to you from
our Mirrors page.

\S{faq-forge}{Question} Why don't you move PuTTY to Github (or some
other well known forge site)?

Primarily, trust. PuTTY is a security product, and as such it is
particularly important to guard the code and the web site against
unauthorised modifications which might introduce subtle security
flaws. Therefore, we prefer that the Git repository, web site and FTP
site remain where they are, under the direct control of system
administrators we know and trust personally.

Large organisations seem less trustworthy to us because they have a
lot of employees, any of whom could attempt an insider attack; because
management can change or companies can be bought out, and a benign
company today could become a malicious one tomorrow.

Github in particular already seems like a dangerously large single
point of failure. I'd rather contribute to the Internet being
distributed than contribute to it being centralised. In addition, the
Github software isn't itself free, so although you can export the
actual source repository itself at any time (every \cq{git clone} does
that), you're locked in once all your other metadata (issues, pull
requests etc) is stored in Github's format on Github's systems.

I know that if you have a Github presence already, it would be most
convenient \e{for you} if everyone else was on Github too so that you
could interact with them all in the same easy way. Sorry about that.
But that seductive ease of use is how large companies attract a large
user base to monetise or exploit later, and we don't want to
participate in that any more than we have to.

\S{faq-mailinglist1}{Question} Why can't I subscribe to the
putty-bugs mailing list?

Because you're not a member of the PuTTY core development team. The
putty-bugs mailing list is not a general newsgroup-like discussion
forum; it's a contact address for the core developers, and an
\e{internal} mailing list for us to discuss things among ourselves.
If we opened it up for everybody to subscribe to, it would turn into
something more like a newsgroup and we would be completely
overwhelmed by the volume of traffic. It's hard enough to keep up
with the list as it is.

\S{faq-mailinglist2}{Question} If putty-bugs isn't a
general-subscription mailing list, what is?

There isn't one, that we know of.

If someone else wants to set up a mailing list or other forum for
PuTTY users to help each other with common problems, that would be
fine with us, though the PuTTY team would almost certainly not have the
time to read it.

\S{faq-donations}{Question} How can I donate to PuTTY development?

Please, \e{please} don't feel you have to. PuTTY is completely free
software, and not shareware. We think it's very important that
\e{everybody} who wants to use PuTTY should be able to, whether they
have any money or not; so the last thing we would want is for a
PuTTY user to feel guilty because they haven't paid us any money. If
you want to keep your money, please do keep it. We wouldn't dream of
asking for any.

Having said all that, if you still really \e{want} to give us money,
we won't argue :-) The easiest way for us to accept donations is if
you send money to \cw{<anakin@pobox.com>} using PayPal
(\W{http://www.paypal.com/}\cw{www.paypal.com}). If you don't like
PayPal, talk to us; we can probably arrange some alternative means.

Small donations (tens of dollars or tens of euros) will probably be
spent on beer or curry, which helps motivate our volunteer team to
continue doing this for the world. Larger donations will be spent on
something that actually helps development, if we can find anything
(perhaps new hardware, or a new version of Windows), but if we can't
find anything then we'll just distribute the money among the
developers. If you want to be sure your donation is going towards
something worthwhile, ask us first. If you don't like these terms,
feel perfectly free not to donate. We don't mind.

\S{faq-permission}{Question} Can I have permission to put PuTTY on a
cover disk / distribute it with other software / etc?

Yes. For most things, you need not bother asking us explicitly for
permission; our licence already grants you permission.

See \k{feedback-permission} for more details.

\S{faq-indemnity}{Question} Can you sign an agreement indemnifying
us against security problems in PuTTY?

No!

A vendor of physical security products (e.g. locks) might plausibly
be willing to accept financial liability for a product that failed
to perform as advertised and resulted in damage (e.g. valuables
being stolen). The reason they can afford to do this is because they
sell a \e{lot} of units, and only a small proportion of them will
fail; so they can meet their financial liability out of the income
from all the rest of their sales, and still have enough left over to
make a profit. Financial liability is intrinsically linked to
selling your product for money.

There are two reasons why PuTTY is not analogous to a physical lock
in this context. One is that software products don't exhibit random
variation: \e{if} PuTTY has a security hole (which does happen,
although we do our utmost to prevent it and to respond quickly when
it does), every copy of PuTTY will have the same hole, so it's
likely to affect all the users at the same time. So even if our
users were all paying us to use PuTTY, we wouldn't be able to
\e{simultaneously} pay every affected user compensation in excess of
the amount they had paid us in the first place. It just wouldn't
work.

The second, much more important, reason is that PuTTY users
\e{don't} pay us. The PuTTY team does not have an income; it's a
volunteer effort composed of people spending their spare time to try
to write useful software. We aren't even a company or any kind of
legally recognised organisation. We're just a bunch of people who
happen to do some stuff in our spare time.

Therefore, to ask us to assume financial liability is to ask us to
assume a risk of having to pay it out of our own \e{personal}
pockets: out of the same budget from which we buy food and clothes
and pay our rent. That's more than we're willing to give. We're
already giving a lot of our spare \e{time} to developing software
for free; if we had to pay our own \e{money} to do it as well, we'd
start to wonder why we were bothering.

Free software fundamentally does not work on the basis of financial
guarantees. Your guarantee of the software functioning correctly is
simply that you have the source code and can check it before you use
it. If you want to be sure there aren't any security holes, do a
security audit of the PuTTY code, or hire a security engineer if you
don't have the necessary skills yourself: instead of trying to
ensure you can get compensation in the event of a disaster, try to
ensure there isn't a disaster in the first place.

If you \e{really} want financial security, see if you can find a
security engineer who will take financial responsibility for the
correctness of their review. (This might be less likely to suffer
from the everything-failing-at-once problem mentioned above, because
such an engineer would probably be reviewing a lot of \e{different}
products which would tend to fail independently.) Failing that, see
if you can persuade an insurance company to insure you against
security incidents, and if the insurer demands it as a condition
then get our code reviewed by a security engineer they're happy
with.

\S{faq-permission-form}{Question} Can you sign this form granting us
permission to use/distribute PuTTY?

If your form contains any clause along the lines of \q{the
undersigned represents and warrants}, we're not going to sign it.
This is particularly true if it asks us to warrant that PuTTY is
secure; see \k{faq-indemnity} for more discussion of this. But it
doesn't really matter what we're supposed to be warranting: even if
it's something we already believe is true, such as that we don't
infringe any third-party copyright, we will not sign a document
accepting any legal or financial liability. This is simply because
the PuTTY development project has no income out of which to satisfy
that liability, or pay legal costs, should it become necessary. We
cannot afford to be sued. We are assuring you that \e{we have done
our best}; if that isn't good enough for you, tough.

The existing PuTTY licence document already gives you permission to
use or distribute PuTTY in pretty much any way which does not
involve pretending you wrote it or suing us if it goes wrong. We
think that really ought to be enough for anybody.

See also \k{faq-permission-general} for another reason why we don't
want to do this sort of thing.

\S{faq-permission-future}{Question} Can you write us a formal notice
of permission to use PuTTY?

We could, in principle, but it isn't clear what use it would be. If
you think there's a serious chance of one of the PuTTY copyright
holders suing you (which we don't!), you would presumably want a
signed notice from \e{all} of them; and we couldn't provide that
even if we wanted to, because many of the copyright holders are
people who contributed some code in the past and with whom we
subsequently lost contact. Therefore the best we would be able to do
\e{even in theory} would be to have the core development team sign
the document, which wouldn't guarantee you that some other copyright
holder might not sue.

See also \k{faq-permission-general} for another reason why we don't
want to do this sort of thing.

\S{faq-permission-general}{Question} Can you sign \e{anything} for
us?

Not unless there's an incredibly good reason.

We are generally unwilling to set a precedent that involves us
having to enter into individual agreements with PuTTY users. We
estimate that we have literally \e{millions} of users, and we
absolutely would not have time to go round signing specific
agreements with every one of them. So if you want us to sign
something specific for you, you might usefully stop to consider
whether there's anything special that distinguishes you from 999,999
other users, and therefore any reason we should be willing to sign
something for you without it setting such a precedent.

If your company policy requires you to have an individual agreement
with the supplier of any software you use, then your company policy
is simply not well suited to using popular free software, and we
urge you to consider this as a flaw in your policy.

\S{faq-permission-assurance}{Question} If you won't sign anything,
can you give us some sort of assurance that you won't make PuTTY
closed-source in future?

Yes and no.

If what you want is an assurance that some \e{current version} of
PuTTY which you've already downloaded will remain free, then you
already have that assurance: it's called the PuTTY Licence. It
grants you permission to use, distribute and copy the software to
which it applies; once we've granted that permission (which we
have), we can't just revoke it.

On the other hand, if you want an assurance that \e{future} versions
of PuTTY won't be closed-source, that's more difficult. We could in
principle sign a document stating that we would never release a
closed-source PuTTY, but that wouldn't assure you that we \e{would}
keep releasing \e{open}-source PuTTYs: we would still have the
option of ceasing to develop PuTTY at all, which would surely be
even worse for you than making it closed-source! (And we almost
certainly wouldn't \e{want} to sign a document guaranteeing that we
would actually continue to do development work on PuTTY; we
certainly wouldn't sign it for free. Documents like that are called
contracts of employment, and are generally not signed except in
return for a sizeable salary.)

If we \e{were} to stop developing PuTTY, or to decide to make all
future releases closed-source, then you would still be free to copy
the last open release in accordance with the current licence, and in
particular you could start your own fork of the project from that
release. If this happened, I confidently predict that \e{somebody}
would do that, and that some kind of a free PuTTY would continue to
be developed. There's already precedent for that sort of thing
happening in free software. We can't guarantee that somebody
\e{other than you} would do it, of course; you might have to do it
yourself. But we can assure you that there would be nothing
\e{preventing} anyone from continuing free development if we
stopped.

(Finally, we can also confidently predict that if we made PuTTY
closed-source and someone made an open-source fork, most people
would switch to the latter. Therefore, it would be pretty stupid of
us to try it.)

\S{faq-export-cert}{Question} Can you provide us with export control
information / FIPS certification for PuTTY?

Some people have asked us for an Export Control Classification Number
(ECCN) for PuTTY.  We don't know whether we have one, and as a team of
free software developers based in the UK we don't have the time,
money, or effort to deal with US bureaucracy to investigate any
further.  We believe that PuTTY falls under 5D002 on the US Commerce
Control List, but that shouldn't be taken as definitive.  If you need
to know more you should seek professional legal advice.  The same
applies to any other country's legal requirements and restrictions.

Similarly, some people have asked us for FIPS certification of the
PuTTY tools.  Unless someone else is prepared to do the necessary work
and pay any costs, we can't provide this.

\S{faq-vendor}{Question} As one of our existing software vendors, can
you just fill in this questionnaire for us?

We periodically receive requests like this, from organisations which
have apparently sent out a form letter to everyone listed in their big
spreadsheet of \q{software vendors} requiring them all to answer some
long list of questions about supported OS versions, paid support
arrangements, compliance with assorted local regulations we haven't
heard of, contact phone numbers, and other such administrivia. Many of
the questions are obviously meaningless when applied to PuTTY (we
don't provide any paid support in the first place!), most of the rest
could have been answered with only a very quick look at our website,
and some we are actively unwilling to answer (we are private
individuals, why would we want to give out our home phone numbers to
large corporations?).

We don't make a habit of responding in full to these questionnaires,
because \e{we are not a software vendor}.

A software \e{vendor} is a company to which you are paying lots of
money in return for some software. They know who you are, and they
know you're paying them money; so they have an incentive to fill in
your forms and questionnaires, to research any local regulations you
cite if they don't already know about them, and generally to provide
every scrap of information you might possibly need in the most
convenient manner for you, because they want to keep being paid.

But we are a team of free software developers, and that means your
relationship with us is nothing like that at all. If you once
downloaded our software from our website, that's great and we hope you
found it useful, but it doesn't mean we have the least idea who you
are, or any incentive to do lots of unpaid work to support our
\q{relationship} with you.

It's not that we are unwilling to \e{provide information}. We put as
much of it as we can on our website for your convenience, and if you
actually need to know some fact about PuTTY which you haven't been
able to find on the website (and which is not obviously inapplicable
to free software in the first place) then please do ask us, and we'll
try to answer as best we can. But we put up the website and this FAQ
precisely so that we \e{don't} have to keep answering the same
questions over and over again, so we aren't prepared to fill in
completely generic form-letter questionnaires for people who haven't
done their best to find the answers here first.

If you work for an organisation which you think might be at risk of
making this mistake, we urge you to reorganise your list of software
suppliers so that it clearly distinguishes paid vendors who know about
you from free software developers who don't have any idea who you are.
Then, only send out these mass mailings to the former.

\S{faq-checksums}{Question} The \c{sha1sums} / \c{sha256sums} / etc
files on your download page don't match the binaries.

People report this every so often, and usually the reason turns out to
be that they've matched up the wrong checksums file with the wrong
binaries.

The PuTTY download page contains more than one version of the
software. There's a \e{latest release} version; there are the
\e{development snapshots}; and when we're in the run-up to making a
release, there are also \e{pre-release} builds of the upcoming new
version. Each one has its own collection of binaries, and its own
collection of checksums files to go with them.

So if you've downloaded the release version of the actual program, you
need the release version of the checksums too, otherwise you will see
a mismatch. Similarly, the development snapshot binaries go with the
development snapshot checksums, and so on. (We've colour-coded the
download page in an effort to reduce this confusion a bit.)

Another thing to watch out for: as of 0.71, executables like
\c{putty.exe} come in two flavours for each platform: the standalone
versions on the website, each of which contains embedded help, and the
versions installed by the installer, which use a separate help file
also in the installer. We provide checksums for both; the latter are
indicated with \cq{(installer version)} after the filename.

If you have double-checked all that, and you still think there's a real
mismatch, then please send us a report carefully quoting everything
relevant:

\b the exact URL you got your binary from

\b the checksum of the binary after you downloaded

\b the exact URL you got your checksums file from

\b the checksum that file says the binary should have.

\H{faq-misc} Miscellaneous questions

\S{faq-openssh}{Question} Is PuTTY a port of \i{OpenSSH}, or based on
OpenSSH or OpenSSL?

No, it isn't. PuTTY is almost completely composed of code written from
scratch for PuTTY. As of 2026, PuTTY and OpenSSH have no code in
common as far as I know.

(In the past, there has been at least one case of both tools sharing
the same piece of third-party code, but not in up-to-date versions.)

\S{faq-ai}{Question} Does PuTTY contain or use any artificial
intelligence (AI) or large language model (LLM)?

No, it does not. PuTTY does not use any AI or LLM during its
operation. No code implementing an AI or LLM system is included in
PuTTY itself, and also, no AI or LLM system elsewhere on the Internet
is consulted by PuTTY when it runs.

PuTTY aims to be reliable, predictable and efficient in its operation.
The 2020s style of AI is bad at all of these things, \e{especially}
\q{efficient}.

PuTTY does not collect any data from its users to communicate to any
host run by the PuTTY developers, for LLM training or for any other
purpose. (See \k{privacy} for more detailed information about what
information PuTTY \e{does} store and transmit, but the short answer
is, it only stores information necessary to do its job, and only
talks over the network to the servers you told it to connect to.)

Of course, after you use PuTTY to connect to a server, \e{that server}
may choose to do AI-related operations, or to collect the data from
your session. PuTTY can do nothing about that (or even detect it
happening), and if you're concerned about it, you'll have to consult
whoever runs your server.

\S{faq-meaning}{Question} What does \q{PuTTY} mean?

It's the name of a popular SSH and Telnet client.  Any other meaning
is in the eye of the beholder.  It's been rumoured that \q{PuTTY}
is the antonym of \q{\cw{getty}}, or that it's the stuff that makes your
Windows useful, or that it's a kind of plutonium Teletype.  We
couldn't possibly comment on such allegations.

\S{faq-pronounce}{Question} How do I pronounce \q{PuTTY}?

Exactly like the English word \q{putty}, which we pronounce
/\u02C8{'}p\u028C{V}ti/.
