Slow connection performance with ssh2

Gert Doering gert at greenie.muc.de
Mon Nov 5 04:00:02 EST 2001


Hi,

On Sun, Nov 04, 2001 at 03:18:00PM +0100, Robert Dahlem wrote:
> SSH2_MSG_KEX_DH_GEX_REQUEST sent         SSH2_MSG_KEX_DH_GEX_REQUEST received
> expecting SSH2_MSG_KEX_DH_GEX_GROUP      SSH2_MSG_KEX_DH_GEX_GROUP sent
> ********* 3.330 seconds                  ********* 3.39 seconds
> dh_gen_key: priv key bits set: 134/256   dh_gen_key: priv_key bits set: 126/256

I have noticed the same - it hangs at these points for a while:

debug: Sending SSH2_MSG_KEX_DH_GEX_REQUEST.
debug: Wait SSH2_MSG_KEX_DH_GEX_GROUP.
debug: Got SSH2_MSG_KEX_DH_GEX_GROUP.
<pause, loooong>
debug: bits set: 1008/2049
debug: Sending SSH2_MSG_KEX_DH_GEX_INIT.
debug: Wait SSH2_MSG_KEX_DH_GEX_REPLY.
<2nd pause, shorter>
debug: Got SSH2_MSG_KEXDH_REPLY.

As my hardware is slower (Sparc LX, NetBSD, 50 MHz CPU) it takes more 
than 2 minutes (!!), which are spent on CPU cycles in ssh and sshd - running
with 95% CPU... - the overall CPU time used by sshd for a successful
connect is about 2:50 minutes

ssh protocol 1 connects take about 5 seconds or so.

Now my question to the experts: is this unavoidable?  Or maybe a
miscompilation of one of the algorithms used on the Sparc hardware?

The openssh version I use is "SSH-1.99-OpenSSH_2.5.1
NetBSD_Secure_Shell-20010614" (which comes with NetBSD 1.5.2).

gert
-- 
USENET is *not* the non-clickable part of WWW!
                                                           //www.muc.de/~gert/
Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert.doering at physik.tu-muenchen.de



More information about the openssh-unix-dev mailing list