Raspberry Pi’s main downside (as far as using it as a router) is that it has only one Ethernet port. This can be overcome by using a USB Ethernet dongle to get an additional Ethernet port. I did not like that idea, because USB dongles are not designed for 24/7 operation. I stumbled upon a forum post that suggested using VLAN tagging to carry two virtual interfaces through the only Ethernet port of the Raspberry Pi, thus eliminating the need for the USB dongle. This article is a quick how-to for setting that up.
