I have X11 forwarding working from my Solaris 8 box to a Windows 2000 client (SSH 2.4). Now I am having difficulty making it work under Linux (Kernel 2.4.2) (SSH 3.0). I've configured everything the same, but when I type xterm from the SSH window, with my Xserver waiting on my 2000 client, I get: xterm Xt error: Can't open display: full.qualified.ssh.server:11.0 The only real difference I can see is that I am going through 2 proxy firewalls to get to this Linux box, and each one modifies my source address as it passes. Eventually, the firewall sees me as if I am coming from 172.16.100.5 - the inside address of the remote proxy firewall. Could this cause a problem with the X session being initiated back through the SSH tunnel? Here are my server configuration parameters: declare -x BASH_ENV="/home/justin/.bashrc" declare -x DISPLAY="fully.qualified.ssh.server:12.0" declare -x HISTSIZE="1000" declare -x HOME="/home/justin" declare -x HOSTNAME="fully.qualified.ssh.server" declare -x HOSTTYPE="i386" declare -x INPUTRC="/etc/inputrc" declare -x KDEDIR="/usr" declare -x LANG="en_US" declare -x LESSOPEN="|/usr/bin/lesspipe.sh %s" declare -x LOGNAME="justin" declare -x LS_COLORS="no=00:fi=00:di=01;34:ln=01;36:pi=40;33:so=01;35:bd=40;33;01:cd=40 ;33;01:or=01;05;37;41:mi=01;05;37;41:ex=01;32:*.cmd=01;32:*.exe=01;32:*.com= 01;32:*.btm=01;32:*.bat=01;32:*.sh=01;32:*.csh=01;32:*.tar=01;31:*.tgz=01;31 :*.arj=01;31:*.taz=01;31:*.lzh=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.gz=01 ;31:*.bz2=01;31:*.bz=01;31:*.tz=01;31:*.rpm=01;31:*.cpio=01;31:*.jpg=01;35:* .gif=01;35:*.bmp=01;35:*.xbm=01;35:*.xpm=01;35:*.png=01;35:*.tif=01;35:" declare -x MACHTYPE="i386-redhat-linux-gnu" declare -x MAIL="/var/spool/mail/justin" declare -x OSTYPE="linux-gnu" declare -x PATH="/usr/bin:/bin:/usr/local/bin:/usr/X11R6/bin:/home/justin/bin" declare -x PWD="/home/justin" declare -x QTDIR="/usr/lib/qt-2.3.0" declare -x SHELL="/bin/bash" declare -x SHLVL="1" declare -x SSH2_CLIENT="172.16.100.5 4241 172.16.100.96 22" declare -x TERM="vt100" declare -x USER="justin" X11 Forwarding is enabled on the client. Thanks, Justin