Document encapsulate type and fqdn option space.

common/dhcp-options.5

@@ -888,6 +888,66 @@ and it should generally be assumed to be an opaque object that is
 administratively guaranteed to be unique to a particular remote end of
 a circuit.
 .RE
+.SH THE CLIENT FQDN SUBOPTIONS
+The Client FQDN option, currently defined in the Internet Draft
+draft-ietf-dhc-fqdn-option-00.txt is not a standard yet, but is in
+sufficiently wide use already that we have implemented it.   Due to
+the complexity of the option format, we have implemented it as a
+suboption space rather than a single option.   In general this
+option should not be configured by the user - instead it should be
+used as part of an automatic DNS update system.
+.PP
+.B option fqdn.no-client-update \fIflag\fB;
+.RS 0.25i
+.PP
+When the client sends this, if it is true, it means the client will not
+attempt to update its A record.   When sent by the server to the client,
+it means that the client \fIshould not\fR update its own A record.
+.RE
+.PP
+.B option fqdn.server-update \fIflag\fB;
+.RS 0.25i
+.PP
+When the client sends this to the server, it is requesting that the server
+update its A record.   When sent by the server, it means that the server
+has updated (or is about to update) the client's A record.
+.RE
+.PP
+.B option fqdn.encoded \fIflag\fB;
+.RS 0.25i
+.PP
+If true, this indicates that the domain name included in the option is
+encoded in DNS wire format, rather than as plain ASCII text.   The client
+normally sets this to false if it doesn't support DNS wire format in the
+FQDN option.   The server should always send back the same value that the
+client sent.   When this value is set on the configuration side, it controls
+the format in which the \fIfqdn.name\fR suboption is encoded.
+.RE
+.PP
+.B option fqdn.rcode1 \fIflag\fB;
+.PP
+.B option fqdn.rcode1 \fIflag\fB;
+.RS 0.25i
+.PP
+These options specify the result of the updates of the A and PTR records,
+respectively, and are only sent by the DHCP server to the DHCP client.
+The values of these fields are those defined in the DNS protocol specification.
+.RE
+.PP
+.B option fqdn.name \fItext\fB;
+.RS 0.25i
+.PP
+Specifies the domain name that the client wishes to use.   This can be a
+fully-qualified domain name, or a single label.   If there is no trailing
+'.' character in the name, it is not fully-qualified, and the server will
+generally update that name in some locally-defined domain.
+.RE
+.PP
+If you wish to use any of these suboptions, we strongly recommend that you
+refer to the Client FQDN option draft (or standard, when it becomes a
+standard) - the documentation here is sketchy and incomplete in comparison,
+and is just intended for reference by people who already understand the
+Client FQDN option specification.
 .SH THE NETWARE/IP SUBOPTIONS
 RFC2242 defines a set of encapsulated options for Novell NetWare/IP
 clients.  To use these options in the dhcp server, specify the option
@@ -1100,6 +1160,31 @@ values must be between 0 and FF.   For example:
 option sql-identification-token code 195 = string;
 option sql-identification-token 17:23:19:a6:42:ea:99:7c:22;
 
+.fi
+.PP
+.B ENCAPSULATION
+.PP
+.B option
+.I new-name
+.B code
+.I new-code
+.B =
+.B encapsulate
+.I identifier
+.B ;
+.PP
+An option whose type is \fBencapsulate\fR will encapsulate the
+contents of the option space specified in \fIidentifier\fR.   Examples
+of encapsulated options in the DHCP protocol as it currently exists
+include the vendor-encapsulated-options option, the netware-suboptions
+option and the relay-agent-information option.
+.nf
+
+option space local;
+option local.demo code 1 = text;
+option local-encapsulation code 197 = encapsulate local;
+option local.demo "demo";
+
 .fi
 .PP
 .B ARRAYS