Is it possible to connect automatically to a server on login without an opened window?

Solution 1:

Instead of whatever method you are doing now to mount the server, I would recommend a script which is launched at login for all users.

Your best options are either a LoginHook or a launchd process installed to /Library/LaunchAgents/

You will then need to figure out the syntax for the mounting the drive.

UPDATE:

I decided I wanted to check this out further myself, and created this launchd script:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>luoma.mount.blackbook</string>
    <key>ProgramArguments</key>
    <array>
        <string>/Users/luomat/Dropbox/bin/mount_blackbook.sh</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
</dict>
</plist>

which I placed at /Library/LaunchAgents/luoma.mount.blackbook.plist (owned by root)

The script can be found at http://f.luo.ma/mount_blackbook.sh (note: script will display in browser window, to download, use click-click/save-as)