Suppressing reverse port-forward connection errors

[Joe K]

Hi,

I have a use case where I am using reverse port-forwarding with the openssh
client, and the server is set up to perform active health checks on some
local ports through the tunnel by opening and closing a TCP connection. It
works fine, except that if a tunneled connection fails, openssh will print
a log to stderr which can clobber an interactive session and necessitate
resizing the terminal or something else to force a redraw of the screen.

These errors can be suppressed using -q (or -y to move them to syslog), but
that also has the side effect of suppressing user-facing messages, such as
auth prompts, which is undesirable.

I'm wondering if it might make sense to allow some degree of customization
on the severity of a failed connection log. In my health checking scenario,
a failed connection is an acceptable outcome, but of course this is not
always the case. Would it make sense to log connection failures at debug1
level (or as errors in syslog only) under some circumstances e.g. if an
interactive session is present? Or a client config option or command-line
flag?

Alternatively, maybe the issue is more so that -q/-y suppresses too much,
and ssh should still print some messages to a tty (if one is present) if
they are intended for user interaction.

Thanks,
Joe Kralicky