The DNS protocol has some time, the RFC which define it, 1034 (concepts and facilities) and 1035 (implementation and specification) are from 1987 and like in all the protocols of that time, security in the comunication wasn't a priority, anyone sniffing the network can see which domains visit everyone, let alone the providers of the DNS service, but it has little solution in the short run, Internet depends on this name sistem and there isn't another better with the required infrastructure, right?
Well, it seems that the Tor SOCKS proxy interface
offers a non standard option (point 2)
which allows to use this network to resolve names, this functionality can be
accessed from the command line through
this capability can be exploited to build a private DNS server which don't
filter the domain name lookups to the network.
Using Twisted is simple to build a this DNS server
to use the Tor network as a resolver backend (is going to be limited to the
A and AAAA records),
this is implemented in Onion-dir
(At Gitorious | At Github).
This may be used adding the parameter
DNSPort 53 to the
the performance may look like an issue but after testing it the results were
pretty good, to a local
bind9 server it takes ~52s to solve every IP from the
"100 most popular webs"
and Tor does it in ~58s (both times with the cache empty), with cached results
it takes ~2.8s for both.
But there is some problems looking up domains like _xmppconnect.gmail.com, the Google XMPP server, domains which on the other hand actually doesn't exists.
$ dig @22.214.171.124 _xmppconnect.gmail.com ; <<>> DiG 9.8.1-P1 <<>> @126.96.36.199 _xmppconnect.gmail.com ; (1 server found) ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 54080 ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0 ;; QUESTION SECTION: ;_xmppconnect.gmail.com. IN A ;; AUTHORITY SECTION: gmail.com. 60 IN SOA ns1.google.com. dns-admin.google.com. 1523590 21600 3600 1209600 300 ;; Query time: 87 msec ;; SERVER: 188.8.131.52#53(184.108.40.206) ;; WHEN: Fri Jun 14 19:44:34 2013 ;; MSG SIZE rcvd: 97
And that seems the main problem left...