DNS Port Randomness Checking
From MyWiki
Web-based
Commandline
Failure:
% dig +short porttest.dns-oarc.net TXT z.y.x.w.v.u.t.s.r.q.p.o.n.m.l.k.j.i.h.g.f.e.d.c.b.a.pt.dns-oarc.net. "68.87.77.132 is POOR: 26 queries in 2.2 seconds from 26 ports with std dev 151.15"
Success:
% dig +short porttest.dns-oarc.net TXT z.y.x.w.v.u.t.s.r.q.p.o.n.m.l.k.j.i.h.g.f.e.d.c.b.a.pt.dns-oarc.net. "141.142.2.2 is GOOD: 26 queries in 1.8 seconds from 26 ports with std dev 20482.70"
Note that the command-line version accepts the "@server" option, which is useful if you have to deal with a mess of primaries, secondaries, forwarders, et cetera:
% dig @NS1 +short porttest.dns-oarc.net TXT % dig @NS2 +short porttest.dns-oarc.net TXT % dig @NS3 +short porttest.dns-oarc.net TXT
