How to disable bell on SSH connections

Gertjan · Dec 27, 2021, 2:15 PM

@networknotwork
The bell generated by pfSense on the pfSense box when you login ?
Or the bell generated by the SSH client when you 'syntax error' or provoke another non-no event ?

networknotwork · Dec 27, 2021, 2:50 PM

@gertjan The bell generated on error conditions (like trying to left arrow/delete past BOL)

networknotwork · Dec 27, 2021, 3:51 PM

@gertjan This may not be a pfsense issue but a Windows issue...ssh runs in a conhost instance which triggers the Windows Critical Stop sound on errors. Windows Terminal has a "disable bell" setting but a regular conhost command prompt window does not, as far as I can tell.

Gertjan · Dec 28, 2021, 9:07 AM

@networknotwork

I'm using Putty myself.
I didn't look, but I'm pretty sure I can inform Putty that, upon reception of '07' == ASCII Bell, I can shut it down.

Yep :

johnpoz · Dec 28, 2021, 3:08 PM

Ok here is a quick easy work around.

after you ssh into pfsense create the .inputrc in what I would assume is the root home directory since that is typically is the account you ssh with (admin). Which is root.

put in this file
bell-style none

Now when you ssh to pfsense using the built in windows ssh, you should not get any bell.

I tested via hearing the bell when hitting backspace while just at the prompt, and also you would hear it when you use tab to complete something. Once put in the .inputrc file setting bell none I no longer heard those.

edit: This doesn't work - not sure what the F I was doing.. See solution later in thread with editing of .tcshrc file with beep setting.

networknotwork · Dec 28, 2021, 2:13 PM

@johnpoz already tried that, didn’t work; I think .inputrc only works for readline, which seems to be a Linux thing? FreeBSD has the kbdcontrol -b off command, which didn’t work either. Weirdly, OpenSSH is presenting itself as an xterm256 terminal, so maybe xset could silence the infernal bell but it’s not installed on pfsense. Anyway I fixed it by muting conhost in the volume mixer!

networknotwork · Dec 28, 2021, 2:17 PM

@gertjan yes, the new Windows Terminal has that option too but the old Windows Console Host (conhost) doesn’t.

johnpoz · Dec 28, 2021, 2:17 PM

@networknotwork not sure what your using/doing then... Because I tested this by opening a cmd prompt in windows 10, ssh to pfsense and heard the bell you were talking about when I just just backspace at the prompt. Or when I did a tab autocomplete..

I then created the .inputrc and no more bell. After I re ssh'd in..

networknotwork · Dec 28, 2021, 2:19 PM

@johnpoz yep did that, but will try again. Are you using the Windows built in ssh (bundled starting with 1809 I think) or another ssh client?

johnpoz · Dec 28, 2021, 2:31 PM

@networknotwork hold - you might be right ;) stupid me was hitting enter not backspace..

doh! Well shit! ;)

sorry about that - need more coffee I guess ;)

johnpoz · Dec 28, 2021, 2:41 PM

@networknotwork ok I think I got it ;)

in your .tcshrc file at the end add

set nobeep

this seems to have done it.

tested with ssh that is part of windows

C:\>ver

Microsoft Windows [Version 10.0.19044.1415]

C:\>ssh -V
OpenSSH_for_Windows_8.1p1, LibreSSL 3.0.2

Or if you like your file to be a bit cleaner looking in the area where its setting prompt and stuff you could add the nobeep

networknotwork · Dec 28, 2021, 2:56 PM

@johnpoz not at my PC but this sounds right, so dang difficult to find stuff specific for tcsh/FreeBSD, just get a deluge of bash/Linux hits…I literally googled (well, DDG’ed) “disable tcsh bell” and didn’t find this.

johnpoz · Dec 28, 2021, 3:15 PM

@networknotwork btw, I tested this with ssh from openssh for windows as well, and it still works - since its related to the shell (tcsh)

C:\>ssh -V
OpenSSH_8.8p1, OpenSSL 1.1.1l  24 Aug 2021

Not sure why the windows built in ssh is so far behind..

Just got a fancy new PC, and still working on getting all the stuff back to the way I like it.. Upon testing this and seeing that the windows version ssh that comes with was so far behind it was time to correct that ;) I normally just use securecrt for my ssh needs, but now and then you need to do stuff from just the command line

Gertjan · Dec 28, 2021, 3:30 PM

@networknotwork said in How to disable bell on SSH connections:

difficult to find stuff specific for tcsh/FreeBSD

It's here https://www.freebsd.org/cgi/man.cgi?tcsh(1).

I've been looking for the beep one myself quiet often, and was thrown of track because what the first line in /etc/passws says : your shell is /bin/sh

But ... when 'root' (or 'admin') logs in, /bin/sh uses /root/.profile that will kick of /etc/rc.initial. rc.initial shows the 'asccii pfsense' menu.
Option 8 of this script will kick of another shell, this time /bin/tcsh

Btw : files like /root/.tcshrc will get overwritten what updating / upgrading and maybe during other circumstances.

johnpoz · Dec 28, 2021, 3:32 PM

@gertjan said in How to disable bell on SSH connections:

files like /root/.tcshrc will get overwritten what updating / upgrading and maybe during other circumstances.

quite true.. so need to keep that in mind going forward.

networknotwork · Dec 28, 2021, 3:35 PM

@johnpoz maybe you guys should just add this to the default .tcshrc :-) I doubt anyone likes the bell!

networknotwork · Dec 28, 2021, 3:48 PM

@gertjan I think /bin/sh in passwd is there for some weird compatibility/historical reasons; it’s usually symlinked to another shell like tcsh/bash in the file system, I don’t think any distro still uses the original sh; the default on FreeBSD is tcsh

johnpoz · Dec 28, 2021, 3:52 PM

@networknotwork said in How to disable bell on SSH connections:

I doubt anyone likes the bell!

hehehe - you never know ;) But sure you could put in a feature request to have that as an option you could turn off or on in the gui..

They have it where you can turn off the bootup/shutdown beep

I would think they could add a option where you configure ssh access to disable that beep ;)

Gertjan · Dec 28, 2021, 4:03 PM

@networknotwork said in How to disable bell on SSH connections:

I don’t think any distro still uses the original sh

Think again.

dump /bin/sh yourself.
The binary will ID itself to you.
It no sym link.

It's 'sh'.

networknotwork · Dec 28, 2021, 5:27 PM

@johnpoz is there a feature request/bug report board? Couldn't find one. Anway, while editing .tcshrc I found a bug: it checks for $term == "xterm" to set key bindings, it should be $term =~ "xterm" to account for xterm-256color etc.

Command line editing wasn't working properly before I made this change, inserting appeared like it was overwriting (not pushing rest of line to the right as I typed) but was actually inserting my typed chars into the line.