Franz Edler writes:
To have the statement "multi on" in /etc/host.conf is perhaps a precondition. But using the command "ifconfig eth0 xx.xx.xx.xx" a second time only changes the allocated IP address to a new one.
try ifconfig eth0:1. if that doesn't work, you may need to recompile your kernel with proper options. this is a general question, so some googling would help.
-- juha