I've seen some issues with dual Real-tek cards in E-Smith boxes, it's been such a long time since I've had that problem that I can't remember what I ended up doing other than getting a 3Com 905C. E-Smith is an excellent, easily configured, secure, and robust implementation of Linux. I'm well versed in Linux and the distributions available and without a doubt would sacrifice $60 for another NIC (You only need one, a RealTek + 3Com will work) for E-Smith.
Hope this helped,
Nathan