+description:
+ Haeredes is primarily useful for ISP network administrators.
+ Customers will occasionally decide to switch hosts without alerting
+ the current host; this can cause two problems:
+
+ * With NS records, the previous host (at the very least) keeps
+ hosting a DNS zone that does nothing. If that host uses their
+ authoritative nameserver as a caching lookup server as well, it
+ may return incorrect results to queries about the domain in
+ question.
+
+ * For MX records, the situation is slightly worse. Most mail servers
+ will immediately accept mail for which the server thinks it is the
+ ultimate destination. If a mail server is configured as the
+ destination for a domain, but it is not the MX for that domain,
+ then mail submitted to that server may possibly be lost. It is
+ therefore important to remove domains from the old mail host as
+ soon as the MX record is changed.
+
+ Haeredes can alert administrators when NS/MX records are changed. More
+ detail and usage examples can be found in the man page.
+
+ /Examples/:
+
+ Make sure example.com has the expected name servers,
+ [ab].iana-servers.net:
+
+ @
+ $ echo \"example.com\" | haeredes a.iana-servers.net b.iana-servers.net
+ @
+
+ Check orlitzky.com against only one of the expected two nameservers:
+
+ @
+ $ echo \"orlitzky.com\" | haeredes dns1.viabit.com
+ Domain \"orlitzky.com.\" delegates somewhere else: \"dns2.viabit.com.\"
+ @
+
+ Check a nonexistent domain (we provide no delegates, since we
+ know .doesnt-exist will not be delegated):
+
+ @
+ $ echo \"foo.doesnt-exist\" | haeredes
+ Domain \"foo.doesnt-exist.\" not delegated.
+ @