[dns-operations] ip id from servers

[sthaug at nethelp.no]

> I can only confirm a few of these from here (Oslo, Norway). What I see
> is pretty bad. *All* of the DNS answers I receive from these 3 servers
> have IP ID 0:
> 
> > 193.0.0.195   ns-pri.ripe.net.
> > 192.54.112.30 h.gtld-servers.net.
> > 202.12.28.140 sec3.apnic.net.

Some more high volume servers which only use IP ID 0 as seen from here:

192.33.14.30	b.gtld-servers.net
192.43.172.30	i.gtld-servers.net
204.74.66.132	ns1.facebook.com
195.166.81.54	de1.sophosxl.com
195.166.81.55	de2.sophosxl.com
150.70.147.168	ns2.hashserver.cs.trendmicro.com
195.41.131.110	d.ns.spamhaus.org

Doing a "tcpdump 'ip[4:2]==0'" on a busy recursive name server can be an
enlightening experience.

Steinar Haug, Nethelp consulting, sthaug at nethelp.no