Barnacle Wifi Tether is a combination of three tools to provide wifi tethering capability on an Android phone. Those three tools are:

• NAT,
• DHCP server, and
• WLAN ad-hoc setup.

In principle, Barnacle Wifi Tether is equivalent to the android-wifi-tether project. However, unlike android-wifi-tether, it does not depend on NETFILTER support in the kernel and thus does not require custom kernel on such phones as Nexus One or Motorola Droid/Milestone.

Moreover, as Barnacle Wifi Tether runs entirely in userspace, it is highly portable between Linux systems (although not portable to non-Linux systems). This feature should make it compatible with a whole bunch of Android phones to come.

Finally, Barnacle Wifi Tether is a true NAT, not a proxy. It works with UDP, TCP and ICMP ECHO (i.e., ping), rather than being limited to HTTP or SOCKS-aware apps (like all non-root tethering apps). Unfortunately, in most cases, this requires superuser (root) privileges.

So, if it requires root, why would you use Barnacle over android-wifi-tether? Barnacle Wifi Tether does not modify any part of the Android system. No need to update the kernel and worry about all of the necessary device drivers working.