Commented the file and added all available options

dnsupdaterc.sample

@@ -1,5 +1,32 @@
+# This is a sample .dnsupdaterc
+
+# Your public hostname and the domain (zone) in which your host
+# lives
+hostname	myserver
 domain		mydomain.com
+
+
+# The keyname and  keysecret  are required when talking to  the
+# nameserver
 keyname		my.key.
 keysecret	some_encrypted_string
-ttl		60
+
-hostname	myserver
+# TTL, time in seconds that an answer about your ip address can
+# be cached by the upstream nameservers
+ttl		3600
+
+# The complete url to a  webpage which displays your ip address
+# http://www.showmyip.com is a free service which returns it to
+# you, but you might want to use something closer to your name-
+# server. 
+ipurl		http://www.showmyip.com/simple
+
+# Quiet mode makes the script run without any output,  great if
+# you call it during boot or from another script
+quiet		false
+
+# You can force an update even if your nameserver is up to date.
+# But all updates causes the nameserver  to  send notifications 
+# the secondary servers  so  it  is  recommended that you leave 
+# this option turned off
+force		false