I have a Red Had Enterprise Linux 5 and a CentOS 5 box, both of which I am trying to configure to automatically connect to a synergy server on startup. I have followed the guide
I use the following on RHEL 5.4 added to /etc/gdm/{Init,PostLogin,PreSession}/Default
/usr/bin/killall synergyc
while [ $(pgrep -x synergyc) ]; do sleep 0.1; done
/usr/bin/synergyc fully.qualified.hostname
In all cases, add the script after any existing script, but before the "exit 0". This works for me. I think it should work as long as you use the Default X Session, if any custom Sessions are used, you will probably have to move the script to the appropriate place.
Try the Synergy Autostart wiki page.
Try adding something like wall 'test'
to the script and see if that shows up on the console. if so, you know the script's being called but it's a problem with synergy. If not, the script isn't being called at all.
Just want to add: when following Matt's advice about putting a call to /usr/bin/synergyc in /etc/gdm/Init/Default, ensure you don't use the -f option there or the script will never exit and you won't be able to log in.