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@@ -2872,16 +2872,84 @@ const std::string HARDCODED_SERVER_ID = "192.0.2.1";</screen>
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<section id="dhcp6-config">
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<title>DHCPv6 Server Configuration</title>
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<para>
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- The DHCPv6 server does not have lease database implemented yet
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- or any support for configuration, so every time the same set
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- of configuration options (including the same fixed address)
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- will be assigned every time.
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+ Once the server is started, its configuration becomes possible. To view
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+ existing configuration, use the following command in <command>bindctl</command>:
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+ <screen>
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+ > <userinput>config show Dhcp6</userinput></screen>
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+ When starting Dhcp6 daemon for the first time, the initial configuration
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+ will be available. It will look similar to this:
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+ <screen>
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+> <userinput>config show Dhcp6</userinput>
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+Dhcp6/interface "eth0" string (default)
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+Dhcp6/renew-timer 1000 integer (default)
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+Dhcp6/rebind-timer 2000 integer (default)
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+Dhcp6/preferred-lifetime 3000 integer (default)
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+Dhcp6/valid-lifetime 4000 integer (default)
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+Dhcp6/subnet6 [] list (default)</screen>
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</para>
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+
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<para>
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- At this stage of development, the only way to alter server
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- configuration is to tweak its source code. To do so, please
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- edit src/bin/dhcp6/dhcp6_srv.cc file, modify the following
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- parameters and recompile:
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+ To change one of the existing configurations, simply follow
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+ the usual <command>bindctl</command> procedure. For example, to make the
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+ leases longer, change their valid-lifetime parameter:
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+ <screen>
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+> <userinput>config set Dhcp6/valid-lifetime 7200</userinput>
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+> <userinput>config commit</userinput></screen>
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+ Please note that most parameters specified in Dhcp6 scope are global
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+ and apply to all defined subnets, unless they are overwritten in a more
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+ specific scope.
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+ </para>
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+
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+ <para>
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+ The essential role of DHCPv6 server is address assignment. The server
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+ has to be configured with at least a subnet and pool of dynamic
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+ addresses that it can manage. For example, let's assume that the server
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+ is connected to a network segment that uses 2001:db8:1::/64
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+ prefix. Administrator of that network decided that addresses from range
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+ 2001:db8:1::1 to 2001:db8:1::ffff are going to be managed by the Dhcp6
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+ server. Such configuration can be achieved in the following way:
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+ <screen>
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+> <userinput>config add Dhcp6/subnet6</userinput>
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+> <userinput>config set Dhcp6/subnet6[0]/subnet "2001:db8:1::/64"</userinput>
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+> <userinput>config set Dhcp6/subnet6[0]/pool6 [ "2001:db8:1::1 - 2001:db8:1::ffff" ]</userinput>
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+> <userinput>config commit</userinput></screen>
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+ Please note that subnet is defined as a simple string, but the pool is
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+ an actual list of pools, therefore must be defined with square
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+ brackets. It is possible to define more than one pool in a
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+ subnet. Continuing the previous example, let's further assume that also
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+ 2001:db8:1:0:5::/80 should be used. It could be written as
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+ 2001:db8:1:0:5:: to 2001:db8:1::5:ffff:ffff:ffff, but typing so many Fs
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+ is cumbersome. It can be expressed simply as 2001:db8:1:0:5::/80. Both
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+ formats are supported by Dhcp6. For example, one could define the following pools:
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+ <screen>
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+> <userinput>config set Dhcp6/subnet6[0]/pool6 [ "2001:db8:1::1 - 2001:db8:1::ffff", "2001:db8:1:0:5::/80" ]</userinput>
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+> <userinput>config commit</userinput></screen>
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+ Number of subnets is not limited, but for performance reasons it is recommended to keep
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+ them as low as possible.
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+ </para>
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+ <para>
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+ The server may be configured to serve more than one subnet. To add a second subnet,
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+ use command similar to the following:
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+ <screen>
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+> <userinput>config add Dhcp6/subnet6</userinput>
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+> <userinput>config set Dhcp6/subnet6[1]/subnet "2001:db8:beef::/48"</userinput>
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+> <userinput>config set Dhcp6/subnet6[1]/pool6 [ "2001:db8:beef::/48" ]</userinput>
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+> <userinput>config commit</userinput></screen>
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+ Arrays are counted from 0. subnet[0] refers to the subnet defined in the
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+ previous example. The <command>config add Dhcp6/subnet6</command> adds
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+ another (second) subnet. It can be referred to as
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+ <command>Dhcp6/subnet6[1]</command>. In this example, we allow server to
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+ dynamically assign all addresses available in the whole subnet. Although
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+ very wasteful, it is certainly a valid configuration to dedicate the
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+ whole /48 subnet for that purpose.
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+ </para>
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+
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+ <para>
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+ Note: Although configuration is now accepted, it is not internally used
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+ by they server yet. At this stage of development, the only way to alter
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+ server configuration is to tweak its source code. To do so, please edit
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+ src/bin/dhcp6/dhcp6_srv.cc file, modify the following parameters and
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+ recompile:
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<screen>
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const std::string HARDCODED_LEASE = "2001:db8:1::1234:abcd";
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const uint32_t HARDCODED_T1 = 1500; // in seconds
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Tomek Mrugalski