We pick l.root-servers.net, one of the 13 root servers (1), and ask it about zipmail.fr and learn that fr is delegated to five name servers (2), so we ask e.ext.nic.fr where we learn that zipmail.fr is delegated to three name servers, including ns2.slconseil.com (3), so we ask that one and get the following answer:
Zipmail.fr is a domain controlled by three domain name servers at slconseil.com having a total of five IP numbers. Some of them are on the same IP network. Incoming mail for zipmail.fr is handled by one mail server at nfrance.com having a total of two IP numbers. Both are on the same IP network. Zipmail.fr has one IP number (80.247.228.60).
One quarter of them use the three mail servers mx1, mx2 and mx3.nfrance.com together, hereafter referred to as "mail server group 1", (example: r-montagne.fr, pressing-blesa.com and patever.fr ). Worth noting is that a third of the domains that use mail server group 1 use name server group 1.
More than one in seven of them use name server group 2 (example: centre-de-radiologie.com, merens-ariege.com and nounours.net ). Worth noting is that most of the domains that use name server group 2 use mail server group 1.
More than one in seven of them are under the tld "net" (example: villenouvelle.net ).
