+extern type serial;
+{{Domain zone serial numbers}}
+extern val serialAuto : serial;
+{{Whenever DNS data changes, choose a sensible serial number automatically.}
+extern val serialConst : int -> serial;
+{{Use this particular serial number.}}
+
+extern type soa;
+{{DNS start-of-authority record}}
+extern val soa : domain -> serial -> int -> int -> int -> int -> soa;
+
+val defaultSoa = soa "ns.hcoop.net" serialAuto 172800 900 1209600 3600;
+
+extern type master;
+{{Information on the master DNS server for a domain}}
+extern val externalMaster : ip -> master;
+{{A server not controlled by domtool will serve as master.}}
+extern val internalMaster : node -> master;
+{{A server controlled by domtool will serve as master.}}
+
+extern type dnsKind;
+{{How should DNS for this domain be handled?}}
+extern val useDns : soa -> master -> [node] -> dnsKind;
+{{We do want DNS services for this domain. Specify the SOA record, information
+ on the server in charge of zone data, and a list of slave servers.}}
+extern val noDns : dnsKind;
+{{No DNS services for this domain.}}
+
+extern val domain : your_domain -> Domain => [Root] {DNS : dnsKind, TTL : int};