[3578] Updated the DHCPv4 user guide with the options always returned.

doc/guide/dhcp4-srv.xml

@@ -715,10 +715,24 @@ temporarily override a list of interface names and listen on all interfaces.
         One of the major features of the DHCPv4 server is to provide configuration
         options to clients.  Although there are several options that require
         special behavior, most options are sent by the server only if the client
-        explicitly requests them.  The following example shows how to
-        configure the addresses of DNS servers, which is one of the most frequently used
-        options. Options specified in this way are considered global and apply
-        to all configured subnets.
+        explicitly requests them using the Parameter Request List option.
+        The last column of the <xref linkend="dhcp4-std-options-list"/> specifies
+        which options can be sent by the server even when they are not
+        requested in the Parameter Request List option, and which are sent only
+        when explicitly requested. These options are marked with the 'true'
+        and 'false' values respectively. One group of options which are
+        sent by the server even when they are not requested are those that
+        require special processing, e.g. Client FQDN option returned if the
+        client has sent Client FQDN option to the server. Another group comprises
+        options with the fixed values specified in the server configuration,
+        e.g. 'domain-name-servers'.
+      </para>
+
+      <para>
+        The following example shows how to configure the addresses of DNS
+        servers, which is one of the most frequently used options. Options
+        specified in this way are considered global and apply to all
+        configured subnets.
 
         <screen>
 "Dhcp4": {
@@ -851,59 +865,61 @@ temporarily override a list of interface names and listen on all interfaces.
       <para>
         <table frame="all" id="dhcp4-std-options-list">
           <title>List of standard DHCPv4 options</title>
-          <tgroup cols='4'>
+          <tgroup cols='5'>
           <colspec colname='name'/>
           <colspec colname='code' align='center'/>
           <colspec colname='type' align='center'/>
           <colspec colname='array' align='center'/>
+          <colspec colname='always-returned' align='center'/>
           <thead>
             <row>
               <entry>Name</entry>
               <entry>Code</entry>
               <entry>Type</entry>
               <entry>Array?</entry>
+              <entry>Returned if not requested?</entry>
             </row>
           </thead>
           <tbody>
-<row><entry>subnet-mask</entry><entry>1</entry><entry>ipv4-address</entry><entry>false</entry></row>
-<row><entry>time-offset</entry><entry>2</entry><entry>int32</entry><entry>false</entry></row>
-<row><entry>routers</entry><entry>3</entry><entry>ipv4-address</entry><entry>true</entry></row>
-<row><entry>time-servers</entry><entry>4</entry><entry>ipv4-address</entry><entry>true</entry></row>
-<row><entry>name-servers</entry><entry>5</entry><entry>ipv4-address</entry><entry>false</entry></row>
-<row><entry>domain-name-servers</entry><entry>6</entry><entry>ipv4-address</entry><entry>true</entry></row>
-<row><entry>log-servers</entry><entry>7</entry><entry>ipv4-address</entry><entry>true</entry></row>
-<row><entry>cookie-servers</entry><entry>8</entry><entry>ipv4-address</entry><entry>true</entry></row>
-<row><entry>lpr-servers</entry><entry>9</entry><entry>ipv4-address</entry><entry>true</entry></row>
-<row><entry>impress-servers</entry><entry>10</entry><entry>ipv4-address</entry><entry>true</entry></row>
-<row><entry>resource-location-servers</entry><entry>11</entry><entry>ipv4-address</entry><entry>true</entry></row>
-<row><entry>host-name</entry><entry>12</entry><entry>string</entry><entry>false</entry></row>
-<row><entry>boot-size</entry><entry>13</entry><entry>uint16</entry><entry>false</entry></row>
-<row><entry>merit-dump</entry><entry>14</entry><entry>string</entry><entry>false</entry></row>
-<row><entry>domain-name</entry><entry>15</entry><entry>fqdn</entry><entry>false</entry></row>
-<row><entry>swap-server</entry><entry>16</entry><entry>ipv4-address</entry><entry>false</entry></row>
-<row><entry>root-path</entry><entry>17</entry><entry>string</entry><entry>false</entry></row>
-<row><entry>extensions-path</entry><entry>18</entry><entry>string</entry><entry>false</entry></row>
-<row><entry>ip-forwarding</entry><entry>19</entry><entry>boolean</entry><entry>false</entry></row>
-<row><entry>non-local-source-routing</entry><entry>20</entry><entry>boolean</entry><entry>false</entry></row>
-<row><entry>policy-filter</entry><entry>21</entry><entry>ipv4-address</entry><entry>true</entry></row>
-<row><entry>max-dgram-reassembly</entry><entry>22</entry><entry>uint16</entry><entry>false</entry></row>
-<row><entry>default-ip-ttl</entry><entry>23</entry><entry>uint8</entry><entry>false</entry></row>
-<row><entry>path-mtu-aging-timeout</entry><entry>24</entry><entry>uint32</entry><entry>false</entry></row>
-<row><entry>path-mtu-plateau-table</entry><entry>25</entry><entry>uint16</entry><entry>true</entry></row>
-<row><entry>interface-mtu</entry><entry>26</entry><entry>uint16</entry><entry>false</entry></row>
-<row><entry>all-subnets-local</entry><entry>27</entry><entry>boolean</entry><entry>false</entry></row>
-<row><entry>broadcast-address</entry><entry>28</entry><entry>ipv4-address</entry><entry>false</entry></row>
-<row><entry>perform-mask-discovery</entry><entry>29</entry><entry>boolean</entry><entry>false</entry></row>
-<row><entry>mask-supplier</entry><entry>30</entry><entry>boolean</entry><entry>false</entry></row>
-<row><entry>router-discovery</entry><entry>31</entry><entry>boolean</entry><entry>false</entry></row>
-<row><entry>router-solicitation-address</entry><entry>32</entry><entry>ipv4-address</entry><entry>false</entry></row>
-<row><entry>static-routes</entry><entry>33</entry><entry>ipv4-address</entry><entry>true</entry></row>
-<row><entry>trailer-encapsulation</entry><entry>34</entry><entry>boolean</entry><entry>false</entry></row>
-<row><entry>arp-cache-timeout</entry><entry>35</entry><entry>uint32</entry><entry>false</entry></row>
-<row><entry>ieee802-3-encapsulation</entry><entry>36</entry><entry>boolean</entry><entry>false</entry></row>
-<row><entry>default-tcp-ttl</entry><entry>37</entry><entry>uint8</entry><entry>false</entry></row>
-<row><entry>tcp-keepalive-interval</entry><entry>38</entry><entry>uint32</entry><entry>false</entry></row>
-<row><entry>tcp-keepalive-garbage</entry><entry>39</entry><entry>boolean</entry><entry>false</entry></row>
+<row><entry>subnet-mask</entry><entry>1</entry><entry>ipv4-address</entry><entry>false</entry><entry>true</entry></row>
+<row><entry>time-offset</entry><entry>2</entry><entry>int32</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>routers</entry><entry>3</entry><entry>ipv4-address</entry><entry>true</entry><entry>true</entry></row>
+<row><entry>time-servers</entry><entry>4</entry><entry>ipv4-address</entry><entry>true</entry><entry>false</entry></row>
+<row><entry>name-servers</entry><entry>5</entry><entry>ipv4-address</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>domain-name-servers</entry><entry>6</entry><entry>ipv4-address</entry><entry>true</entry><entry>true</entry></row>
+<row><entry>log-servers</entry><entry>7</entry><entry>ipv4-address</entry><entry>true</entry><entry>false</entry></row>
+<row><entry>cookie-servers</entry><entry>8</entry><entry>ipv4-address</entry><entry>true</entry><entry>false</entry></row>
+<row><entry>lpr-servers</entry><entry>9</entry><entry>ipv4-address</entry><entry>true</entry><entry>false</entry></row>
+<row><entry>impress-servers</entry><entry>10</entry><entry>ipv4-address</entry><entry>true</entry><entry>false</entry></row>
+<row><entry>resource-location-servers</entry><entry>11</entry><entry>ipv4-address</entry><entry>true</entry><entry>false</entry></row>
+<row><entry>host-name</entry><entry>12</entry><entry>string</entry><entry>false</entry><entry>true</entry></row>
+<row><entry>boot-size</entry><entry>13</entry><entry>uint16</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>merit-dump</entry><entry>14</entry><entry>string</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>domain-name</entry><entry>15</entry><entry>fqdn</entry><entry>false</entry><entry>true</entry></row>
+<row><entry>swap-server</entry><entry>16</entry><entry>ipv4-address</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>root-path</entry><entry>17</entry><entry>string</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>extensions-path</entry><entry>18</entry><entry>string</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>ip-forwarding</entry><entry>19</entry><entry>boolean</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>non-local-source-routing</entry><entry>20</entry><entry>boolean</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>policy-filter</entry><entry>21</entry><entry>ipv4-address</entry><entry>true</entry><entry>false</entry></row>
+<row><entry>max-dgram-reassembly</entry><entry>22</entry><entry>uint16</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>default-ip-ttl</entry><entry>23</entry><entry>uint8</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>path-mtu-aging-timeout</entry><entry>24</entry><entry>uint32</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>path-mtu-plateau-table</entry><entry>25</entry><entry>uint16</entry><entry>true</entry><entry>false</entry></row>
+<row><entry>interface-mtu</entry><entry>26</entry><entry>uint16</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>all-subnets-local</entry><entry>27</entry><entry>boolean</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>broadcast-address</entry><entry>28</entry><entry>ipv4-address</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>perform-mask-discovery</entry><entry>29</entry><entry>boolean</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>mask-supplier</entry><entry>30</entry><entry>boolean</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>router-discovery</entry><entry>31</entry><entry>boolean</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>router-solicitation-address</entry><entry>32</entry><entry>ipv4-address</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>static-routes</entry><entry>33</entry><entry>ipv4-address</entry><entry>true</entry><entry>false</entry></row>
+<row><entry>trailer-encapsulation</entry><entry>34</entry><entry>boolean</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>arp-cache-timeout</entry><entry>35</entry><entry>uint32</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>ieee802-3-encapsulation</entry><entry>36</entry><entry>boolean</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>default-tcp-ttl</entry><entry>37</entry><entry>uint8</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>tcp-keepalive-interval</entry><entry>38</entry><entry>uint32</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>tcp-keepalive-garbage</entry><entry>39</entry><entry>boolean</entry><entry>false</entry><entry>false</entry></row>
 
           </tbody>
           </tgroup>
@@ -913,65 +929,70 @@ temporarily override a list of interface names and listen on all interfaces.
       <para>
         <table frame="all" id="dhcp4-std-options-list-part2">
           <title>List of standard DHCPv4 options (continued)</title>
-          <tgroup cols='4'>
+          <tgroup cols='5'>
           <colspec colname='name'/>
           <colspec colname='code'/>
           <colspec colname='type'/>
           <colspec colname='array'/>
+          <colspec colname='always-returned' align='center'/>
           <thead>
             <row>
               <entry>Name</entry>
               <entry>Code</entry>
               <entry>Type</entry>
               <entry>Array?</entry>
+              <entry>Returned if not requested?</entry>
             </row>
           </thead>
           <tbody>
 
-<row><entry>nis-domain</entry><entry>40</entry><entry>string</entry><entry>false</entry></row>
-<row><entry>nis-servers</entry><entry>41</entry><entry>ipv4-address</entry><entry>true</entry></row>
-<row><entry>ntp-servers</entry><entry>42</entry><entry>ipv4-address</entry><entry>true</entry></row>
-<row><entry>vendor-encapsulated-options</entry><entry>43</entry><entry>empty</entry><entry>false</entry></row>
-<row><entry>netbios-name-servers</entry><entry>44</entry><entry>ipv4-address</entry><entry>true</entry></row>
-<row><entry>netbios-dd-server</entry><entry>45</entry><entry>ipv4-address</entry><entry>true</entry></row>
-<row><entry>netbios-node-type</entry><entry>46</entry><entry>uint8</entry><entry>false</entry></row>
-<row><entry>netbios-scope</entry><entry>47</entry><entry>string</entry><entry>false</entry></row>
-<row><entry>font-servers</entry><entry>48</entry><entry>ipv4-address</entry><entry>true</entry></row>
-<row><entry>x-display-manager</entry><entry>49</entry><entry>ipv4-address</entry><entry>true</entry></row>
-<row><entry>dhcp-requested-address</entry><entry>50</entry><entry>ipv4-address</entry><entry>false</entry></row>
-<!-- Lease time should not be configured by a user.
-<row><entry>dhcp-lease-time</entry><entry>51</entry><entry>uint32</entry><entry>false</entry></row>
+<row><entry>nis-domain</entry><entry>40</entry><entry>string</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>nis-servers</entry><entry>41</entry><entry>ipv4-address</entry><entry>true</entry><entry>false</entry></row>
+<row><entry>ntp-servers</entry><entry>42</entry><entry>ipv4-address</entry><entry>true</entry><entry>false</entry></row>
+<row><entry>vendor-encapsulated-options</entry><entry>43</entry><entry>empty</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>netbios-name-servers</entry><entry>44</entry><entry>ipv4-address</entry><entry>true</entry><entry>false</entry></row>
+<row><entry>netbios-dd-server</entry><entry>45</entry><entry>ipv4-address</entry><entry>true</entry><entry>false</entry></row>
+<row><entry>netbios-node-type</entry><entry>46</entry><entry>uint8</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>netbios-scope</entry><entry>47</entry><entry>string</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>font-servers</entry><entry>48</entry><entry>ipv4-address</entry><entry>true</entry><entry>false</entry></row>
+<row><entry>x-display-manager</entry><entry>49</entry><entry>ipv4-address</entry><entry>true</entry><entry>false</entry></row>
+<!-- Lease time and requested address should not be configured by a user.
+<row><entry>dhcp-requested-address</entry><entry>50</entry><entry>ipv4-address</entry><entry>false</entry><entry>true</entry></row>
+<row><entry>dhcp-lease-time</entry><entry>51</entry><entry>uint32</entry><entry>false</entry><entry>true</entry></row>
 -->
-<row><entry>dhcp-option-overload</entry><entry>52</entry><entry>uint8</entry><entry>false</entry></row>
+<row><entry>dhcp-option-overload</entry><entry>52</entry><entry>uint8</entry><entry>false</entry><entry>false</entry></row>
 <!-- Message Type, Server Identifier and Parameter Request List should not be configured by a user.
-<row><entry>dhcp-message-type</entry><entry>53</entry><entry>uint8</entry><entry>false</entry></row>
-<row><entry>dhcp-server-identifier</entry><entry>54</entry><entry>ipv4-address</entry><entry>false</entry></row>
-<row><entry>dhcp-parameter-request-list</entry><entry>55</entry><entry>uint8</entry><entry>true</entry></row>
+<row><entry>dhcp-message-type</entry><entry>53</entry><entry>uint8</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>dhcp-server-identifier</entry><entry>54</entry><entry>ipv4-address</entry><entry>false</entry><entry>true</entry></row>
+<row><entry>dhcp-parameter-request-list</entry><entry>55</entry><entry>uint8</entry><entry>true</entry><entry>true</entry></row>
 -->
-<row><entry>dhcp-message</entry><entry>56</entry><entry>string</entry><entry>false</entry></row>
-<row><entry>dhcp-max-message-size</entry><entry>57</entry><entry>uint16</entry><entry>false</entry></row>
+<row><entry>dhcp-message</entry><entry>56</entry><entry>string</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>dhcp-max-message-size</entry><entry>57</entry><entry>uint16</entry><entry>false</entry><entry>false</entry></row>
 <!-- Renewal and rebinding time should not be configured by a user.
-<row><entry>dhcp-renewal-time</entry><entry>58</entry><entry>uint32</entry><entry>false</entry></row>
-<row><entry>dhcp-rebinding-time</entry><entry>59</entry><entry>uint32</entry><entry>false</entry></row>
+<row><entry>dhcp-renewal-time</entry><entry>58</entry><entry>uint32</entry><entry>false</entry><entry>true</entry></row>
+<row><entry>dhcp-rebinding-time</entry><entry>59</entry><entry>uint32</entry><entry>false</entry><entry>true</entry></row>
 -->
-<row><entry>vendor-class-identifier</entry><entry>60</entry><entry>binary</entry><entry>false</entry></row>
+<row><entry>vendor-class-identifier</entry><entry>60</entry><entry>binary</entry><entry>false</entry><entry>false</entry></row>
 <!-- Client identifier should not be configured by a user.
-<row><entry>dhcp-client-identifier</entry><entry>61</entry><entry>binary</entry><entry>false</entry></row>
+<row><entry>dhcp-client-identifier</entry><entry>61</entry><entry>binary</entry><entry>false</entry><entry>true</entry></row>
+-->
+<row><entry>nwip-domain-name</entry><entry>62</entry><entry>string</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>nwip-suboptions</entry><entry>63</entry><entry>binary</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>tftp-server-name</entry><entry>66</entry><entry>string</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>boot-file-name</entry><entry>67</entry><entry>string</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>user-class</entry><entry>77</entry><entry>binary</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>fqdn</entry><entry>81</entry><entry>record</entry><entry>false</entry><entry>true</entry></row>
+<!-- Relay Agent Information is not configured by the user.
+It is merely echoed by the server
+<row><entry>dhcp-agent-options</entry><entry>82</entry><entry>empty</entry><entry>false</entry><entry>false</entry></row>
 -->
-<row><entry>nwip-domain-name</entry><entry>62</entry><entry>string</entry><entry>false</entry></row>
-<row><entry>nwip-suboptions</entry><entry>63</entry><entry>binary</entry><entry>false</entry></row>
-<row><entry>tftp-server-name</entry><entry>66</entry><entry>string</entry><entry>false</entry></row>
-<row><entry>boot-file-name</entry><entry>67</entry><entry>string</entry><entry>false</entry></row>
-<row><entry>user-class</entry><entry>77</entry><entry>binary</entry><entry>false</entry></row>
-<row><entry>fqdn</entry><entry>81</entry><entry>record</entry><entry>false</entry></row>
-<row><entry>dhcp-agent-options</entry><entry>82</entry><entry>empty</entry><entry>false</entry></row>
-<row><entry>authenticate</entry><entry>90</entry><entry>binary</entry><entry>false</entry></row>
-<row><entry>client-last-transaction-time</entry><entry>91</entry><entry>uint32</entry><entry>false</entry></row>
-<row><entry>associated-ip</entry><entry>92</entry><entry>ipv4-address</entry><entry>true</entry></row>
-<row><entry>subnet-selection</entry><entry>118</entry><entry>ipv4-address</entry><entry>false</entry></row>
-<row><entry>domain-search</entry><entry>119</entry><entry>binary</entry><entry>false</entry></row>
-<row><entry>vivco-suboptions</entry><entry>124</entry><entry>binary</entry><entry>false</entry></row>
-<row><entry>vivso-suboptions</entry><entry>125</entry><entry>binary</entry><entry>false</entry></row>
+<row><entry>authenticate</entry><entry>90</entry><entry>binary</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>client-last-transaction-time</entry><entry>91</entry><entry>uint32</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>associated-ip</entry><entry>92</entry><entry>ipv4-address</entry><entry>true</entry><entry>false</entry></row>
+<row><entry>subnet-selection</entry><entry>118</entry><entry>ipv4-address</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>domain-search</entry><entry>119</entry><entry>binary</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>vivco-suboptions</entry><entry>124</entry><entry>binary</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>vivso-suboptions</entry><entry>125</entry><entry>binary</entry><entry>false</entry><entry>false</entry></row>
           </tbody>
           </tgroup>
         </table>