Firewall support is preliminary and is relevant to XEN containers
only. A suitable rspec fragment for your node is:

    <emulab:firewall style=closed'>
      <emulab:exception port='80' direction='incoming' ip='myip'/>
    </emulab:firewall>

won't bother to explain, its obvious and going to change pretty
quickly. Well, I should mention that "myip" means to replace the
ip with the ip address of the caller.

Linkedelay support allows passing through basic Emulab traffic shaping
parameters, in a linkdelay only configuration.