[dns-operations] 0x20 fun and games

[sthaug at nethelp.no]

0x20 games seem to be an excellent way of detecting load balancers and
similar boxes that do bad things with your queries. I'm testing Unbound
1.0.2 with 0x20 turned on here. In addition to boxes which downcase
everything (e.g. the name servers for leaseweb.net, com.tw among others)
I found the following rather nasty load balancer case:

{62.13.40.45,194.14.242.129,194.14.243.129} NS for qstream-down.qbrick.com:

 qstream-down.qbrick.com A -> OK
 qstream-down.qbrick.coM A -> NXDOMAIN

I'm tempted to say everbody should turn on 0x20 so that we can get these
problem cases discovered and fixed as soon as possible.

Steinar Haug, Nethelp consulting, sthaug at nethelp.no