faq.but

大名鼎鼎的远程登录软件putty的Symbian版源码

Unfortunately, \c{screen} is one exception: it uses the alternate
screen, but it's still usually helpful to have PuTTY's scrollback
continue working. The simplest solution is to go to the Features
control panel and tick \q{Disable switching to alternate terminal
screen}. (See \k{config-features-altscreen} for more details.)

The reason why this only started to be a problem in 0.54 is because
\c{screen} typically uses an unusual control sequence to switch to
the alternate screen, and previous versions of PuTTY did not support
this sequence.

\S{faq-alternate-localhost}{Question} Since I upgraded Windows XP
to Service Pack 2, I can't use addresses like \cw{127.0.0.2}.

Some people who ask PuTTY to listen on localhost addresses other
than \cw{127.0.0.1} to forward services such as SMB and Windows
Terminal Services have found that doing so no longer works since
they upgraded to WinXP SP2.

This is apparently an issue with SP2 that is acknowledged by Microsoft
in MS Knowledge Base article
\W{http://support.microsoft.com/default.aspx?scid=kb;en-us;884020}{884020}.
The article links to a fix you can download.

(\e{However}, we've been told that SP2 \e{also} fixes the bug that
means you need to use non-\cw{127.0.0.1} addresses to forward
Terminal Services in the first place.)

\S{faq-missing-slash}{Question} PSFTP commands seem to be missing a
directory separator (slash). 

Some people have reported the following incorrect behaviour with
PSFTP:

\c psftp> pwd
\e        iii
\c Remote directory is /dir1/dir2
\c psftp> get filename.ext
\e        iiiiiiiiiiiiiiii
\c /dir1/dir2filename.ext: no such file or directory

This is not a bug in PSFTP. There is a known bug in some versions of
portable OpenSSH
(\W{http://bugzilla.mindrot.org/show_bug.cgi?id=697}{bug 697}) that
causes these symptoms; it appears to have been introduced around
3.7.x. It manifests only on certain platforms (AIX is what has been
reported to us).

There is a patch for OpenSSH attached to that bug; it's also fixed in
recent versions of portable OpenSSH (from around 3.8).

\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
floppy).

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

PuTTY will leave some Registry entries, and a random seed file, on
the PC (see \k{faq-settings}). If you are using PuTTY on a public
PC, or somebody else's PC, you might want to clean these up when you
leave. You can do that automatically, by running the command
\c{putty -cleanup}.

\S{faq-dsa}{Question} How come PuTTY now supports DSA, when the
website used to say how insecure it was?

DSA has a major weakness \e{if badly implemented}: it relies on a
random number generator to far too great an extent. If the random
number generator produces a number an attacker can predict, the DSA
private key is exposed - meaning that the attacker can log in as you
on all systems that accept that key.

The PuTTY policy changed because the developers were informed of
ways to implement DSA which do not suffer nearly as badly from this
weakness, and indeed which don't need to rely on random numbers at
all. For this reason we now believe PuTTY's DSA implementation is
probably OK. However, if you have the choice, we still recommend you
use RSA instead.

\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.

\H{faq-admin} Administrative questions

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

No, thank you. Even if you can find one (most of them seem to have
been registered already, by people who didn't ask whether we
actually wanted it before they applied), we're happy with the PuTTY
web site being exactly where it is. It's not hard to find (just type
\q{putty} into \W{http://www.google.com/}{google.com} and we're the
first link returned), and we don't believe the administrative hassle
of moving the site would be worth the benefit.

In addition, if we \e{did} want a custom domain name, we would want
to run it ourselves, so we knew for certain that it would continue
to point where we wanted it, and wouldn't suddenly change or do
strange things. Having it registered for us by a third party who we
don't even know is not the best way to achieve this.

\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.

One very nice effect of the Google ranking mechanism is that by and
large, the most popular web sites get the highest rankings. This
means that when an ordinary person does a search, the top item in
the search is very likely to be a high-quality site or the site they
actually wanted, rather than the site which paid the most money for
its ranking.

The PuTTY web site is held in high esteem by Google, for precisely
this reason: lots of people have linked to it simply because they
like PuTTY, without us ever having to ask anyone to link to us. We
feel that it would be an abuse of this esteem to use it to boost the
ranking of random advertisers' web sites. If you want your web site
to have a high Google ranking, we'd prefer that you achieve this the
way we did - by being good enough at what you do that people will
link to you simply because they like you.

In particular, we aren't interested in trading links for money (see
above), and we \e{certainly} aren't interested in trading links for
other links (since we have no advertising on our web site, our
Google ranking is not even directly worth anything to us). 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 mirror of the PuTTY web
site, we're \e{definitely} interested.

\S{faq-sourceforge}{Question} Why don't you move PuTTY to
SourceForge?

Partly, because we don't want to move the web site location (see
\k{faq-domain}).

Also, security reasons. 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 CVS repository, web site and
FTP site remain where they are, under the direct control of system
administrators we know and trust personally, rather than being run
by a large organisation full of people we've never met and which is
known to have had breakins in the past.

No offence to SourceForge; I think they do a wonderful job. But
they're not ideal for everyone, and in particular they're not ideal
for us.

\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.  It's probably better to use the established
newsgroup \cw{comp.security.ssh} for this purpose.

\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{<[e-mail]>} using PayPal
(\W{http://www.paypal.com/}\cw{www.paypal.com}). Alternatively, if
you don't trust PayPal, you could donate through e-gold
(\W{http://www.e-gold.com}\cw{www.e-gold.com}): deposit your
donation in account number 174769, then send us e-mail to let us
know you've done so (otherwise we might not notice for months!).

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 copy of Windows XP), 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. You need not bother asking us explicitly for permission. You
already have permission. Redistribution of the unmodified PuTTY
binary in this way is entirely permitted by our licence (see
\k{licence}), and you are welcome to do it as much as you like.

If you are distributing PuTTY within your own organisation, or for
use with your own product, then we recommend (but do not insist)
that you offer your own first-line technical support, to answer
questions directly relating to the interaction of PuTTY with your
particular environment. If your users mail us directly, we won't be
able to give them very much help about things specific to your own
setup.

\H{faq-misc} Miscellaneous questions

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

No, it isn't. PuTTY is almost completely composed of code written
from scratch for PuTTY. The only code we share with OpenSSH is the
detector for SSH1 CRC compensation attacks, written by CORE SDI S.A.

\S{faq-sillyputty}{Question} Where can I buy silly putty?

You're looking at the wrong web site; the only PuTTY we know about
here is the name of a computer program.

If you want the kind of putty you can buy as an executive toy, the
PuTTY team can personally recommend Thinking Putty, which you can
buy from Crazy Aaron's Putty World, at
\W{http://www.puttyworld.com}\cw{www.puttyworld.com}.

\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}t\u026A{I}/.