Samsung Scanner in Your Network Despite Firewall With Manual Setup

​To manually detect a Samsung network scanner with sane, you can try this method:

echo 'tcp scx' | sudo tee -a /etc/sane.d/xerox_mfp.conf

Replace "scx" with ​the IP address or resolvable hostname of your scanner. Try to ping the host, e.g. "ping scx" before you enter it here.

This assumes using the drivers from www.bchemnet.com/suldr. For some services, you may have to restart the service or your computer. It fixed using the scanner with an active firewall for me.