I'm using a pi as a firewall between my house and a 30 meter ethernet cable to my shed. I wanted ethernet to my shed but found that physical security of ethern

I'm using a pi as a firewall between my house and a 30 meter ethernet cable to my shed. I wanted ethernet to my shed but found that physical security of ethernet was a little pricey. I'm using an old pi, a cheap ethernet dongle I got in lild in a sale and ipfire to create an isolated network in the shed.