One of the things that happens every night on a Linux server is the administrator gets an emailed log file summary from a process known as “Logwatch” with lots of useful information such as a list of sites that have tried to guess passwords, hack your web server and so on. It also tells the current disk usage , warns about things getting out of kilter…
It’s generally a good idea to find what’s causing problems and fix them, but sometimes the answer is to stop reporting the problem.
Amongst the things that are reported when you run a name service are the hosts tHat try to use your server as a recursive resolver (you don’t want to let anyone other than your own customers do this or you might become part of a DDoS attack) and the servers that give malformed responses.
Now as I run a pretty up-to date name server I tend to believe the server when it reports that it’s getting random responses, and had written code to collate the reports to make an exclusion list of servers not to talk to.
Top of the bad response list were ns?.msft.net. These are the name servers which connect you to hotmail.com and outlook.com, and while blocking them gives a noticeable improvement in SPAM volume, ultimately there are people who want to use Hotmail.com despite it’s dreadful record of accounts being hacked