The Raspberry Pi is extremely suitable to serve all kinds of handy things on your home network that usually would require a server. This is mainly due to its very low power consumption, but also because it is very small and can be hidden in a lot of places. For example, if you own a USB scanner you would have to connect it to the system you'd currently like to scan on. With the Raspberry Pi you can have your scanner on a central place and use it to scan from anywhere within your network. Anywhere outside of your network would work as well, but is doesn't make much sense as you'd have to place the documents on the scanner remotely

1. On your Raspberry, install saned:

   sudo apt-get install sane

2. Edit /etc/default/saned and set RUN to yes.
3. After the installation go to the dicectory /etc/sane.d and edit the saned.conf. Add the following line to allow scanning from your network:

   aaa.bbb.ccc.ddd/mm

4. If you also use IPv6 add this line as well:

   [aaaa:bbbb:cccc:dddd::]/mm

5. So, for example (these are not real IP addresses of course):

   192.168.123.0/24

   [2001:db8::]/64

6. Afterwards, restart saned

   /etc/init.d/saned restart

And you should be good to go.

On the client side installation and configuration is even easier. Just install sane and maybe simple-scan (great application!), afterwards edit the /etc/sane.d/net.conf and add (e.g. as a last line) the name or IP address of your server.

That's is, now you're good to go!