Control-c not work under openssh?

Garrick James garrick at
Tue Jul 18 09:28:57 EST 2000

Sorry this reply is pieced together wierd--I had to cut and paste from the
web archives.

Anyway, I am seeing this same control-C problem, also.  Was there ever
any fix found?

My details:

When making ssh connections to openssh-2.1.1p4 servers running on Solaris
2.6, Control-C no longer causes an interrupt.  The stty settings are
reported as the same that are reported when just using telnet to the box
(and control-c works then).

Strangely enough, it seems to be somewhat dependant on the client being
used.  When the client is openssh-2.1.1p4 (on Solaris 2.6), the problem
exists (that is, control-c does not work).  When the client is Tera Term
Pro with the ssh1 add-on (Win32 client), the problem does NOT exist (that
is, control-c works fine).  When the client is SecureCRT 3.1 (Win32
client), the problem DOES exist.  When the client is openssh-2.1.1p4 (on
Solaris 2.6) and the server is openssh-2.1.1p4 (on Linux), the problem
does NOT exist.  Strange matrix, eh?

When the problem does exist, 'su - username' seems to fix it (regardless
of the client :).  Needless to say, it is very annoying to have to su
everytime I log in just to get control-c working.

Anyway, has anyone found the reason for this problem?  Anybody have an
idea how to fix it?

-Garrick James

----- Previous Message(s) in Thread -----

>>>"JH" == John Horne <J.Horne at> writes:

 JH> I'm using openSSH 2.1.1p2 from my Linux PC to Solaris 7 and 8 systems
 JH> 2.1.1p1). No problem, except that if I run a program on the Sun,
having used
 JH> slogin to connect to it, and then try and issue a control-c to break
 JH> the program it seems to be ignored. I can control-z and then kill the


I got the same problem and want to add some details that might help to
track down the problem.

We have a heterogeneous environment of Solaris 2.6 and 8 and Linux, most
using ssh 1.x and some OpenSSH 2.1.1p1. After some testing, we are
certain that the problem is with the OpenSSH daemon. The ctrl-c is
ignored whenever the target host runs this sshd on Solaris 8 (didn't try
2.6; no problem on Linux). The problem exists, if the user has a Bourne
shell or a bash. However, if you invoke (in a broken tty/shell) either
/bin/su or zsh, ctrl-c works again. The ssty -a output in a broken and
not-broken tty are the same.

<rough guess> 
sshd might be doing something wrong when initializing the
pty/tty. A truss/strace comparison of Solaris 8 and Linux shows that the
Linux sshd does some more ioctls on the tty during login. Maybe su and
zsh repair the problem by default but bash and sh don't.  
</rough guess>

Hope that helps someone who know more about this stuff ... ;-)

Cheers, Nils

More information about the openssh-unix-dev mailing list