I've been reading past topics on how to set your nic to full-duplex and 
it doesn't seem all that hard, but I'm running into a problem...

When I execute this command: ifconfig em0 media 100BaseTX mediaopt 
full-duplex
With em0 being my lan interface, I loose any and all connections to the 
firewall. I can't access the webGUI, I can't ping it, I can't run any 
other commands, and I got absolutely no resulting output (not even an 
error). This is a built-in nic on a Dell GX260 which is supposed to be 
gigabit (though I'm running it at 100Mbps) and should most definitely 
support full-duplex.

Any suggestions?