I'm trying to decide on which distro would have the best
1. Server hardware support(Dell PowerEdge 1800)
2. Setup for a NAT, IE, cable to modem goes into one port, cable to a switch, and the rest of the network goes out the other, basically making the computer a router
3. Capable of pushing out pxelinux over TFTP, meaning it also would have to act as the DHCP server(at least to my knowledge)

If anyone can point me to A) A good distro for those, and B) a nice tutorial for setting those up, the NAT is particularly troubling me, I'd definite appreciate it.