faq.but

putty

source in such a way that it will run under \i{Win32s} (an extension to
Windows 3.1 to let you run 32-bit programs). In order to do this
you'll need the right kind of C compiler - modern versions of Visual
C at least have stopped being backwards compatible to Win32s. Also,
the last time we tried this it didn't work very well.

If you're interested in running PuTTY under Windows 3.1, help and
testing in this area would be very welcome!

\S{faq-mac-port}{Question} Will there be a port to the \I{Mac OS}Mac?

There are several answers to this question:

\b The Unix/Gtk port is already fully working under Mac OS X as an X11
application.

\b A native (Cocoa) Mac OS X port has been started. It's just about
usable, but is of nowhere near release quality yet, and is likely to
behave in unexpected ways. Currently it's unlikely to be completed
unless someone steps in to help.

\b A separate port to the classic Mac OS (pre-OSX) is also in
progress; it too is not ready yet.

\S{faq-epoc}{Question} Will there be a port to EPOC?

I hope so, but given that ports aren't really progressing very fast
even on systems the developers \e{do} already know how to program
for, it might be a long time before any of us get round to learning
a new system and doing the port for that.

However, some of the work has been done by other people, and a beta
port of PuTTY for the Nokia 9200 Communicator series is available
from \W{http://s2putty.sourceforge.net/}\cw{http://s2putty.sourceforge.net/}

\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.

\S{faq-vb}{Question} Is the SSH or Telnet code available as a Visual
Basic component?

No, it isn't. None of the PuTTY team uses Visual Basic, and none of
us has any particular need to make SSH connections from a Visual
Basic application. In addition, all the preliminary work to turn it
into a DLL would be necessary first; and furthermore, we don't even
know how to write VB components.

If someone offers to do some of this work for us, we might consider
it, but unless that happens I can't see VB integration being
anywhere other than the very bottom of our priority list.

\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.

This is what CVS for Windows does, for example.

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

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

For most purposes, PuTTY can be considered to be an \cw{xterm}
terminal.

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).

By default, PuTTY announces its terminal type to the server as
\c{xterm}. If you have a problem with this, you can reconfigure it
to say something else; \c{vt220} might help if you have trouble.

\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}
in your Windows home directory (\c{%HOMEDRIVE%\\%HOMEPATH%}), or in
the actual Windows directory (such as \c{C:\\WINDOWS}) if the home
directory doesn't exist, for example if you're using Win95. 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}.

\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?

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?

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.

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 the documentation.

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 traditional SCP protocol, this is 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"

If PSCP is using the newer SFTP protocol, none of this is a problem,
and 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" .

\H{faq-trouble} Troubleshooting

\S{faq-incorrect-mac}{Question} Why do I see \q{Incorrect MAC
received on packet}?

One possible cause of this that used to be common is a bug in old
SSH-2 servers distributed by \cw{ssh.com}. (This is not the only
possible cause; see \k{errors-crc} in the documentation.)
Version 2.3.0 and below of their SSH-2 server
constructs Message Authentication Codes in the wrong way, and
expects the client to construct them in the same wrong way. PuTTY
constructs the MACs correctly by default, and hence these old
servers will fail to work with it.