We've noticed that often when there is a hit range:
there is only one IP for each domain
there is a range of about 20-30 of those
and that this does not seem to be that common. Let's see if that is a reasonable fingerprint or not.
Note that although this is the most common case, we have found multiple hits that viewdns.info maps to the same IP.
First we create a table u (unique) that only have domains which are the only domain for an IP, let's see by how much that lowers the 191 M total unique domains:
time sqlite3 u.sqlite 'create table t (d text, i text)'
time sqlite3 av.sqlite -cmd "attach 'u.sqlite' as u" "insert into u.t select min(d) as d, min(i) as i from t where d not like '%.%.%' group by i having count(distinct d) = 1"
The not like '%.%.%' removes subdomains from the counts so that CGI comms are still included, and distinct in count(distinct is because we have multiple entries at different timestamps for some of the hits.
Let's start with the 208 subset to see how it goes:
time sqlite3 av.sqlite -cmd "attach 'u.sqlite' as u" "insert into u.t select min(d) as d, min(i) as i from t where i glob '208.*' and d not like '%.%.%' and (d like '%.com' or d like '%.net') group by i having count(distinct d) = 1"
OK, after we fixed bugs with the above we are down to 4 million lines with unique domain/IP pairs and which contains all of the original hits! Almost certainly more are to be found!
The numbers of the first column are the IPs as a 32-bit integer representation, which is more useful to search for ranges in.
To make a histogram with the distribution of the single hostname IPs:
#!/usr/bin/env bash
bin=$((2**24))
sqlite3 2013-dns-census-a-novirt.sqlite -cmd '.mode csv' >2013-dns-census-a-novirt-hist.csv <<EOF
select i, sum(cnt) from (
select floor(i/${bin}) as i,
count(*) as cnt
from t
group by 1
union
select *, 0 as cnt from generate_series(0, 255)
)
group by i
EOF
gnuplot \
-e 'set terminal svg size 1200, 800' \
-e 'set output "2013-dns-census-a-novirt-hist.svg"' \
-e 'set datafile separator ","' \
-e 'set tics scale 0' \
-e 'unset key' \
-e 'set xrange[0:255]' \
-e 'set title "Counts of IPs with a single hostname"' \
-e 'set xlabel "IPv4 first byte"' \
-e 'set ylabel "count"' \
-e 'plot "2013-dns-census-a-novirt-hist.csv" using 1:2:1 with labels' \
;
Which gives the following useless noise, there is basically no pattern:
