After a bit of research, I've found a few mechanisms for setting up more
than one IP address on an ethernet none of which work on RiscBSD.  There
is a vif patch that can be applied to the kernel, otherwise things like
Solaris support ifconfig ea0:x commands where x is a numbered virtual
interface. man ifconfig mentions alias but it's only a mention and I can't
get it to work. Is there a mechanism for virtual IP addresses that works
on RiscBSD?

Stephen Borrill