I use a Xircom RealPort Ethernet 10/100+Modem56 (REM56G-100) PCMCIA card that has a packet driver for DOS and a TP-LINK TL-MR3040 mobile router that has a ethernet socket, mTCP does the rest on software layer. Yes, a lot of people install Linux on their Librettos, but I wanted something oldschool and be able to play DOS games.