PuTTY allows the server to send control codes that let it take over the mouse and use it for purposes other than copy and paste. Applications which use this feature include the text-mode web browser links, the Usenet newsreader trn version 4, and the file manager mc (Midnight Commander).
If you find this feature inconvenient, you can disable it using the ‘Disable xterm-style mouse reporting’ control. With this box ticked, the mouse will always do copy and paste in the normal way.
Note that even if the application takes over the mouse, you can still manage PuTTY's copy and paste by holding down the Shift key while you select and paste, unless you have deliberately turned this feature off (see
section 4.11.3
).
4.6.3 Disabling remote terminal resizing
PuTTY has the ability to change the terminal's size and position in response to commands from the server. If you find PuTTY is doing this unexpectedly or inconveniently, you can tell PuTTY not to respond to those server commands.
4.6.4 Disabling switching to the alternate screen
Many terminals, including PuTTY, support an ‘alternate screen’. This is the same size as the ordinary terminal screen, but separate. Typically a screen-based program such as a text editor might switch the terminal to the alternate screen before starting up. Then at the end of the run, it switches back to the primary screen, and you see the screen contents just as they were before starting the editor.
Some people prefer this not to happen. If you want your editor to run in the same screen as the rest of your terminal activity, you can disable the alternate screen feature completely.
4.6.5 Disabling remote window title changing
PuTTY has the ability to change the window title in response to commands from the server. If you find PuTTY is doing this unexpectedly or inconveniently, you can tell PuTTY not to respond to those server commands.
4.6.6 Response to remote window title querying
PuTTY can optionally provide the xterm service of allowing server applications to find out the local window title. This feature is disabled by default, but you can turn it on if you really want it.
NOTE that this feature is a potential security hazard. If a malicious application can write data to your terminal (for example, if you merely cat a file owned by someone else on the server machine), it can change your window title (unless you have disabled this as mentioned in
section 4.6.5
) and then use this service to have the new window title sent back to the server as if typed at the
keyboard. This allows an attacker to fake keypresses and potentially cause your server-side applications to do things you didn't want. Therefore this feature is disabled by default, and we recommend you do not set it to ‘Window title’ unless you really know what you are doing.
There are three settings for this option:
‘None’
PuTTY makes no response whatsoever to the relevant escape sequence. This may upset server-side software that is expecting some sort of response.
‘Empty string’
PuTTY makes a well-formed response, but leaves it blank. Thus, server-side software that expects a response is kept happy, but an attacker cannot influence the response string. This is probably the setting you want if you have no better ideas.
‘Window title’
PuTTY responds with the actual window title. This is dangerous for the reasons described above.
4.6.7 Disabling destructive backspace
Normally, when PuTTY receives character 127 (^?) from the server, it will perform a ‘destructive backspace’: move the cursor one space left and delete the character under it. This can apparently cause problems in some applications, so PuTTY provides the ability to configure character 127 to perform a normal backspace (without deleting a character) instead.