Figuring out a UML's UMID (Unique Machine ID)
There are a few ways to do this:
Choosing an IP for a TUN/TAP interface
Choose an IP address that's part of your local IP range. It can't be
in use by another host on the network. However, it can be the same as
another of the host's network interfaces. Reusing the IP address from
the host eth0 is popular when free IP addresses are in short supply.
Choosing an IP for a UML eth interface
The easiest thing to do is pick a IP that's on your local network and
unused anywhere else, including the host. In particular, it must be
different from the IP address you gave the host end of the TUN/TAP
If you don't have a local network, just a single IP given to you by
your ISP, then use an address in the 192.168.x.x or 10.x.x.x ranges.
Installing the uml_utilities on the host
You may already have it - look for /usr/bin/uml_net or
/usr/bin/uml_mconsole. If you need humfsify, then the package you
have installed is probably not new enough and you should download and
host% bunzip2 uml_utilities_20070815.tar.bz2
host% tar xf uml_utilities_20070815.tar
host% cd tools-20070815/
Install, as root
host# make install
Setting up NAT on the host
Setting up NAT for the benefit of a UML is most often needed when the
host is the only machine on your network and the only IP address you
use is the one assigned to it by your ISP. In this case, the
following command will set up masquerading for the UML, if eth0 is the
device that you use to communicate with the Internet.
host# iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
If eth0 isn't your connection to the rest of the world, then change
the "eth0" accordingly. If you're on a dialup connection, then "ppp0"
is likely to be correct.