We pick g.root-servers.net, one of the 13 root servers (1), and ask it about aasfn.sm and learn that sm is delegated to four name servers (2), so we ask dns.intelcom.sm and get the following answer:
Aasfn.sm is a domain controlled by two domain name servers at omniway.sm and intelcom.sm. Both are on the same IP network. Incoming mail for aasfn.sm is handled by three mail servers at telecomitalia.sm. All three of them are on the same IP network.
The three mail servers smtp20, smtp21 and smtp22.telecomitalia.sm together
Five of the more than hundred domains that use mail server group 1 point only to the IP number 151.1.33.15 (example: ad301.sm, contatto.sm and wolf.sm ).
The two name servers dns.intelcom.sm and dns.omniway.sm together
Nine of the several hundred of domains that use name server group 1 point only to the IP number 62.149.197.228 (example: titanocanali.sm ).