[networking-guide] master: Configure dhcrelay as a DHCPv4 and BOOTP relay agent (1d2cc6a)

[stephenw]

Repository : http://git.fedorahosted.org/cgit/docs/networking-guide.git

On branch  : master

> ---------------------------------------------------------------
commit 1d2cc6a7013c65d0e75f58ceae01063504c5176d
Author: Stephen Wadeley <swadeley(a)redhat.com&gt;
Date:   Sat Jul 26 15:22:33 2014 +0200

    Configure dhcrelay as a DHCPv4 and BOOTP relay agent
    
    Thanks to jpopelka for this section.


> ---------------------------------------------------------------
 en-US/DHCP_Servers.xml |   48 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 48 insertions(+), 0 deletions(-)

diff --git a/en-US/DHCP_Servers.xml b/en-US/DHCP_Servers.xml
index 1e2dcc5..5cf12e9 100644
--- a/en-US/DHCP_Servers.xml
+++ b/en-US/DHCP_Servers.xml
@@ -309,9 +309,57 @@ Then, as the <systemitem
class="username">root</systemitem> user, restart the se
 
       <para>The DHCP Relay Agent listens for DHCP requests on all interfaces unless
the interfaces are specified in <filename>/etc/sysconfig/dhcrelay</filename>
with the <computeroutput>INTERFACES</computeroutput> directive.</para>
 
+      <para>
+     <application>dhcrelay</application> can either be run as a
<systemitem class="protocol">DHCPv4</systemitem> and <systemitem
class="protocol">BOOTP</systemitem> relay agent (by default) or as a
<systemitem class="protocol">DHCPv6</systemitem> relay agent (with
<option>-6</option> argument). To see the usage message, issue the command
<command>dhcrelay -h</command>.
+      </para>
+
       <para>To start the DHCP Relay Agent, use the following command:</para>
       <screen><command>systemctl start
dhcrelay.service</command></screen>
     </section>
+
+<section id="Configure_dhcrelay_as_a_DHCPv4_and_BOOTP_relay_agent">
+      <title>Configure dhcrelay as a DHCPv4 and BOOTP relay agent</title>
+<para>
+  To run <application>dhcrelay</application> in <systemitem
class="protocol">DHCPv4</systemitem> and <systemitem
class="protocol">BOOTP</systemitem> mode specify the servers to which
the requests should be forwarded to.
+Copy and then edit the <filename>dhcrelay.service</filename> file as the
<systemitem class="username">root</systemitem> user:
+<screen>~]# <command>cp /lib/systemd/system/dhcrelay.service
/etc/systemd/system/</command>
+~]# <command>vi
/etc/systemd/system/dhcrelay.service</command></screen>
+</para>
+<para>
+Edit the <option>ExecStart</option> option under section [Service] and add
one or more server <systemitem class="protocol">IPv4</systemitem>
addresses to the end of the line, for example:
+<synopsis>ExecStart=/usr/sbin/dhcrelay -d --no-pid 192.168.1.1</synopsis>
+</para>
+<para>
+If you also want to specify interfaces where the DHCP Relay Agent listens for
<systemitem class="protocol">DHCP</systemitem> requests, add them to
the <option>ExecStart</option> option with <option>-i</option>
argument, for example:
+<synopsis>ExecStart=/usr/sbin/dhcrelay -d --no-pid 192.168.1.1 -i
em1</synopsis>
+For other options see the <filename>dhcrelay(8)</filename> man page.
+</para>
+    <para>
+To activate the changes made, as the <systemitem
class="username">root</systemitem> user, restart the service:
+<screen>~]# <command>systemctl --system daemon-reload</command>
+~]# <command>systemctl restart dhcrelay</command></screen>
+</para>
+   </section>
+   <section id="Configure_dhcrelay_as_a_DHCPv6_relay_agent">
+      <title>Configure dhcrelay as a DHCPv6 relay agent</title>
+<para>
+  To run <application>dhcrelay</application> in <systemitem
class="protocol">DHCPv6</systemitem> mode add the
<option>-6</option> argument and specify the <quote>lower
interface</quote> (on which queries will be received from clients or from other
relay agents) and the <quote>upper interface</quote> (to which queries from
clients and other relay agents should be forwarded).
+
+Copy <filename>dhcrelay.service</filename> to
<filename>dhcrelay6.service</filename> and edit it as the <systemitem
class="username">root</systemitem> user:
+<screen>~]# <command>cp /lib/systemd/system/dhcrelay.service
/etc/systemd/system/dhcrelay6.service</command>
+~]# <command>vi
/etc/systemd/system/dhcrelay6.service</command></screen>
+</para>
+<para>
+Edit the <option>ExecStart</option> option under section [Service] add
<option>-6</option> argument and add the <quote>lower
interface</quote> and <quote>upper interface</quote> interface, for
example:
+<synopsis>ExecStart=/usr/sbin/dhcrelay -d --no-pid -6 -l em1 -u
em2</synopsis>
+For other options see the <filename>dhcrelay(8)</filename> man page.
+</para>
+    <para>
+To activate the changes made, as the <systemitem
class="username">root</systemitem> user, restart the service:
+<screen>~]# <command>systemctl --system daemon-reload</command>
+~]# <command>systemctl restart dhcrelay6</command></screen>
+</para>
+    </section>
   </section>
 
   <section