Can I use a serial port as TCP/IP interface on Red Hat Linux?

Background

We want to run an FTP server on a Red Hat Enterprise OS. The problem is, the machine we have does not have an Ethernet port/interface (please don't ask why; it's just a project requirement).

We only have a serial port.

Question

Is there COTS / open source software that I can use to make serial port "look" like a an Ethernet port? My project is commercial. We run Red Hat Enterprise Linux 5.3.

Note: Pardon me if my post title is unclear. If you can think of a better title, please suggest or simply change the title.

You should also be able to use PPP (point-to-point protocol) to another endpoint over a serial connection.

I found a couple of things, but I'm not sure if it's the answer to my question. Please comment as you see fit:

• ser2net
• Eltima Serial To Ethernet

I also found another question asked on SO, but I'm not sure if it's related to what I'm trying to do: