Question : Problem: Speed issue with SSH tunnel (local port forwarding) using OpenSSH on Windows 2003

I'm using copSSH 2.0.1 (a repack of OpenSSH 5.1p1, link: http://www.itefix.no/i2/copssh) and plink 0.6 (part of putty) to create an SSH tunnel to forward a local port to a server and then run rsync 3.0.5 to mirror large data sets. Bother servers are running Windows Server 2003 (copSSH comes with the needed cygwin DLLs)

When testing across a 100MB LAN rsync will perform at 3-8MB/sec depending on network conditions. If I use the SSH tunnel between the same computers (and the same network conditions) I will only get 400-600KB/sec. (Around 400 when using SSH-2, around 600 when forcing SSH-1.) Speeds are even worse when going across the Internet (much slower than FTP transfers between the same host.)

When troubleshooting, if I use the ssh client that ships with OpenSSH my speeds are marginally improved over plink.exe - but I need plink due to a requirement for automated login with username/password, and RSA keys cannot be used for authentication.

The command I'm using to call plink is:
plink.exe -l [username] -pw [password] server.x.com -N -v -L 1873:127.0.0.1:873

Below is my sshd_config. Is there anything I can do to speed up OpenSSH? I'm quite experienced in Windows, but I have limited experience configuring any kind of SSH server. I'm assuming rsync is not the problem since it works at speeds I would be pleased with when not using the SSH tunnel.

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#	$OpenBSD: sshd_config,v 1.74 2006/07/19 13:07:10 dtucker Exp $
 
# This is the sshd server system-wide configuration file.  See
# sshd_config(5) for more information.
 
# This sshd was compiled with PATH=/bin:/usr/sbin:/sbin:/usr/bin
 
# The strategy used for options in the default sshd_config shipped with
# OpenSSH is to specify options with their default value where
# possible, but leave them commented.  Uncommented options change a
# default value.
 
#Port 22
#Protocol 2,1
#AddressFamily any
#ListenAddress 0.0.0.0
#ListenAddress ::
 
# HostKey for protocol version 1
#HostKey /etc/ssh_host_key
# HostKeys for protocol version 2
#HostKey /etc/ssh_host_rsa_key
#HostKey /etc/ssh_host_dsa_key
 
# Lifetime and size of ephemeral version 1 server key
#KeyRegenerationInterval 1h
#ServerKeyBits 768
 
# Logging
# obsoletes QuietMode and FascistLogging
#SyslogFacility AUTH
#LogLevel INFO
 
# Authentication:
 
#LoginGraceTime 2m
#PermitRootLogin yes
PermitRootLogin no
#StrictModes yes
#MaxAuthTries 6
 
#RSAAuthentication yes
#PubkeyAuthentication yes
#AuthorizedKeysFile	.ssh/authorized_keys
 
# For this to work you will also need host keys in /etc/ssh_known_hosts
#RhostsRSAAuthentication no
# similar for protocol version 2
#HostbasedAuthentication no
# Change to yes if you don't trust ~/.ssh/known_hosts for
# RhostsRSAAuthentication and HostbasedAuthentication
#IgnoreUserKnownHosts no
IgnoreUserKnownHosts yes
# Don't read the user's ~/.rhosts and ~/.shosts files
#IgnoreRhosts yes
 
# To disable tunneled clear text passwords, change to no here!
#PasswordAuthentication yes
#PermitEmptyPasswords no
 
# Change to no to disable s/key passwords
#ChallengeResponseAuthentication yes
 
# Kerberos options
#KerberosAuthentication no
#KerberosOrLocalPasswd yes
#KerberosTicketCleanup yes
#KerberosGetAFSToken no
 
# GSSAPI options
#GSSAPIAuthentication no
#GSSAPICleanupCredentials yes
 
# Set this to 'yes' to enable PAM authentication, account processing, 
# and session processing. If this is enabled, PAM authentication will 
# be allowed through the ChallengeResponseAuthentication and
# PasswordAuthentication.  Depending on your PAM configuration,
# PAM authentication via ChallengeResponseAuthentication may bypass
# the setting of "PermitRootLogin without-password".
# If you just want the PAM account and session checks to run without
# PAM authentication, then enable this but set PasswordAuthentication
# and ChallengeResponseAuthentication to 'no'.
#UsePAM no
 
#AllowTcpForwarding yes
#GatewayPorts no
#X11Forwarding no
#X11DisplayOffset 10
#X11UseLocalhost yes
#PrintMotd yes
#PrintLastLog yes
#TCPKeepAlive yes
#UseLogin no
#UsePrivilegeSeparation yes
UsePrivilegeSeparation yes
#PermitUserEnvironment no
#Compression delayed
#ClientAliveInterval 0
#ClientAliveCountMax 3
#UseDNS yes
#PidFile /var/run/sshd.pid
#MaxStartups 10
#PermitTunnel no
 
# no default banner path
#Banner /some/path
Banner /etc/banner.txt
 
# override default of no subsystems
Subsystem	sftp	/bin/sftp-server
 
# Example of overriding settings on a per-user basis
#Match User anoncvs
#	X11Forwarding no
#	AllowTcpForwarding no
#	ForceCommand cvs server

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Answer : Problem: Speed issue with SSH tunnel (local port forwarding) using OpenSSH on Windows 2003

(Instead of rRlt, try with a. And enable z to get file compression during transfer to save bandwidth. And use --modify-window=1 to lower "last modified" check sensitivity of 1 sec, to avoid rsync to be fooled in transferring unchanged files due to NTFS time check mechanism. And don't use server and sender options, they are for internal use and for debugging).

Probably yes, launching a per user daemon is part of the problem due to the permission system of Windows. I had to use it during my thesis and had the same issues. I think I ended in giving up using -e ssh option.
Remember that you are under a simulated UNIX environment, it's not 100% native for Windows. Use a tunnel to solve the problem as stated in the man ("For another way to encrypt a daemon transfer, consider using ssh to tunnel a local port to a remote machine and configure a normal rsync daemon on that remote host to only allow connections from "localhost".")
:/