Nick Couchman commented on GUACAMOLE-269:
So, there's something a little strange here that I'm having a hard time
figuring out. It looks like, in most cases, the information about the
backspace key and/or stty erase is automatically passed through from the SSH
client to the server. I've yet to figure out exactly how this works, but
here's what I've done:
- On my Linux system (OpenSuSE, XFCE, etc.), SSH into an AIX machine.
Backspace key works as expected, and "stty -a" reveals that erase=^?. I can
also do the "Ctrl-V + Backspace" key combo to print out what Backspace is
- On my Windows system (Windows 10, PuTTY), open a SSH system into the same AIX
machine with the default settings. Backspace key, again, works as expected,
"stty -a" shows erase=^?, and the magic combo shows that Backspace is sending
- On my Windows system, change the PuTTY settings such that Backspace sends
Ctrl-H instead of Ctrl-? (the default), then open the SSH session to the same
AIX host. Backspace works as expected, but "stty -a" shows erase=^h, and the
magic key code shows Backspace is sending ^h.
- In Guacamole, connect to the same AIX system, and Backspace just results in
^? being displayed repeatedly across the screen. "stty -a" shows erase=^h, but
Backspace is not sending that.
- In Guacamole, connect to a Linux system, and Backspace works as it should,
"stty -a" shows erase=^?, and that's what Backspace is sending.
>From all of this testing, I gather that there is something that both either
>the Linux terminal and/or SSH client, and the Windows PuTTY client, are
>providing to the SSH server on AIX that guides how it sets up the stty info,
>and that Guacamole (libssh2) is not providing this information, or is
>providing the wrong information. At first I thought maybe it was the terminal
>name/type that was being provided, since "linux" is what Guacamole sends, but
>is not a known terminal type on AIX, so I tweaked the Guacamole client/server
>code to allow this to be configurable, and tried several values (linux, vt100,
>vt220, xterm, and xterm-256color), but this did not change the behavior on AIX
>at all - it still defaults to ^h as the erase character, no matter what value
>the terminal is set to.
So, not sure what's going on, here - could be the version of libssh2 I'm using,
I suppose, or that there's something that the Guacamole calls to libssh are not
configuring properly before opening the connection. Not sure. Any hints would
> Add support for alternative backspace/delete control codes
> Key: GUACAMOLE-269
> URL: https://issues.apache.org/jira/browse/GUACAMOLE-269
> Project: Guacamole
> Issue Type: Improvement
> Components: SSH, Telnet, Terminal
> Reporter: Michael Jumper
> Assignee: Nick Couchman
> Priority: Minor
> *The description of this issue was copied from
> [GUAC-1003|https://glyptodon.org/jira/browse/GUAC-1003], an issue in the JIRA
> instance used by the Guacamole project prior to its acceptance into the
> Apache Incubator.*
> Comments, attachments, related issues, and history from prior to acceptance
> *have not been copied* and can be found instead at the original issue.
> On some devices, such as Comware devices, the backspace and delete keys will
> not work, as such devices use Ctrl-H or Ctrl-D for these respectively.
> Guacamole should provide configuration options for SSH and telnet, such that
> different control codes can be used for backspace/delete for the sake of
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