Clarifications for DNS-auth in man-page.

man/dnsmasq.8

@@ -553,7 +553,8 @@ Define a DNS zone for which dnsmasq acts as authoritative server. Locally define
 will be served, except that A and AAAA records must be in one of the
 specified subnets, or in a subnet corresponding to a contructed DHCP
 range. The subnet(s) are also used to define in-addr.arpa and
-ipv6.arpa domains which are served for reverse-DNS queries.
+ipv6.arpa domains which are served for reverse-DNS queries. For IPv4
+subnets, the prefix length is limited to the values 8, 16 or 24.
 .TP
 .B --auth-soa=<serial>[,<hostmaster>[,<refresh>[,<retry>[,<expiry>]]]]
 Specify fields in the SOA record associated with authoritative
@@ -1753,7 +1754,7 @@ we have
 .fi
 
 .nf
-our.zone.com             A    192.0.43.10
+our.zone.com             A    1.2.3.4
 our.zone.com            NS    our.zone.com
 .fi
 
@@ -1766,11 +1767,23 @@ record. If the external address is static, this can be done with an
 .B /etc/hosts 
 entry or 
 .B --host-record.
-If the external address is dynamic,
-then it must be done using something like
 
 .nf
-.B --interface-name=our.zone.com,eth0
+.B auth-server=our.zone.com,eth0
+.B host-record=our.zone.com,1.2.3.4
+.B auth-zone=our.zone.com,1.2.3.0/24
+.fi
+
+If the external address is dynamic, the address
+associated with our.zone.com must be derived from the address of the
+relvant interface. This is done using 
+.B interface-name
+Something like:
+
+.nf
+.B auth-server=our.zone.com,eth0
+.B interface-name=our.zone.com,eth0
+.B auth-zone=our.zone.com,1.2.3.0/24
 .fi
 
 Our final configuration builds on that above, but also adds a