Of course, you want SNMP monitors get you and email as an alert, you have to setup auth DNS with xyz.local and use it in air-gapped environments for your alert mails. Hard drive failure?, RX/TX errors on a switch port? fire up mail over SMTP with an SNMP agent, etc. the list goes on and on.

Network without DNS is un-useable. Apologies for my english, it is not my native language.