DNS tunneling transport (like iodine, dnscat)

DNS-based pluggable transport.

Encode data in recursive DNS queries and responses. Your local recursive resolver sends your packets to the right place. A DNS bridge would be an authoritative name server for a particular domain; users would configure a domain rather than an IP address in their Bridge lines. Tools already exist to do DNS tunneling, for example ​iodine and ​dnscat. Probably requires a reliability layer and periodic polling by the client.

Provides a way for users behind restrictive firewalls to connect to Tor at the expense of speed.

Mailing list discussions: [tor-dev] obfsproxy dns transport ​https://lists.torproject.org/pipermail/tor-dev/2014-February/006250.html (Feb 2014)

using OzymanDNS to access Tor via DNS ​https://lists.torproject.org/pipermail/tor-talk/2006-January/007124.html (Jan 2006)