iodine lets you tunnel IPv4 data through a DNS server. This can be usable in different situations where internet access is firewalled, but DNS queries are allowed.

It runs on Linux, Mac OS X, FreeBSD, NetBSD, OpenBSD and Windows and needs a TUN/TAP device. The bandwidth is asymmetrical with limited upstream and up to 1 Mbit/s downstream.

Compared to other DNS tunnel implementations, iodine offers:

Higher performance

iodine uses the NULL type that allows the downstream data to be sent without encoding. Each DNS reply can contain over a kilobyte of compressed payload data.

Portability

iodine runs on many different UNIX-like systems as well as on Win32. Tunnels can be set up between two hosts no matter their endianness or operating system.

Security

iodine uses challenge-response login secured by MD5 hash. It also filters out any packets not coming from the IP used when logging in.

Less setup

iodine handles setting IP number on interfaces automatically, and up to 16 users can share one server at the same time. Packet size is automatically probed for maximum downstream throughput.

See the README, the CHANGELOG and the man page