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author | Yuriy Andamasov <andamasov@gmail.com> | 2019-01-20 16:17:30 +0100 |
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committer | GitHub <noreply@github.com> | 2019-01-20 16:17:30 +0100 |
commit | 612ab4def61755afc369c8e226588b15db0bc751 (patch) | |
tree | 8356346a5b7a4b51339a4975f10da3f4b9123ef9 /docs/services/dhcp-relay.rst | |
parent | ce02006259e45ea9b0ab5f30ac3f1639d2338505 (diff) | |
parent | 1ac4afa392eb4c077507cf3866ebc1b8b3cb1793 (diff) | |
download | vyos-documentation-612ab4def61755afc369c8e226588b15db0bc751.tar.gz vyos-documentation-612ab4def61755afc369c8e226588b15db0bc751.zip |
Merge pull request #7 from kmpm/festures/split-services
services in own folder
Diffstat (limited to 'docs/services/dhcp-relay.rst')
-rw-r--r-- | docs/services/dhcp-relay.rst | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/docs/services/dhcp-relay.rst b/docs/services/dhcp-relay.rst new file mode 100644 index 00000000..c6bccb22 --- /dev/null +++ b/docs/services/dhcp-relay.rst @@ -0,0 +1,165 @@ + + +DHCP Relay +---------- + +If you want your router to forward DHCP requests to an external DHCP server +you can configure the system to act as a DHCP relay agent. The DHCP relay +agent works with IPv4 and IPv6 addresses. + +All interfaces used for the DHCP relay must be configured. See +https://wiki.vyos.net/wiki/Network_address_setup. + +DHCP relay example +^^^^^^^^^^^^^^^^^^ + +.. figure:: /_static/images/service_dhcp-relay01.png + :scale: 80 % + :alt: DHCP relay example + + DHCP relay example + +In this example the interfaces used for the DHCP relay are eth1 and eth2. The +router receives DHCP client requests on eth1 and relays them through eth2 to +the DHCP server at 10.0.1.4. + +Configuration +^^^^^^^^^^^^^ + +Enable DHCP relay for eth1 and eth2: + +.. code-block:: sh + + set service dhcp-relay interface eth1 + set service dhcp-relay interface eth2 + +Set the IP address of the DHCP server: + +.. code-block:: sh + + set service dhcp-relay server 10.0.1.4 + +The router should discard DHCP packages already containing relay agent +information to ensure that only requests from DHCP clients are forwarded: + +.. code-block:: sh + + set service dhcp-relay relay-options relay-agents-packets discard + +Commit the changes and show the results: + +.. code-block:: sh + + commit + show service dhcp-relay + interface eth1 + interface eth2 + server 10.0.1.4 + relay-options { + relay-agents-packets discard + } + +The DHCP relay agent can be restarted with: + +.. code-block:: sh + + restart dhcp relay-agent + +DHCPv6 relay example +^^^^^^^^^^^^^^^^^^^^ + +.. figure:: /_static/images/service_dhcpv6-relay01.png + :scale: 80 % + :alt: DHCPv6 relay example + + DHCPv6 relay example + +In this example DHCPv6 requests are received by the router on eth1 +(`listening interface`) and forwarded through eth2 (`upstream interface`) to +the external DHCPv6 server at 2001:db8:100::4. + +Configuration +************* + +Set eth1 to be the listening interface for the DHCPv6 relay: + +.. code-block:: sh + + set service dhcpv6-relay listen-interface eth1 + +Set eth2 to be the upstream interface and specify the IPv6 address of +the DHCPv6 server: + +.. code-block:: sh + + set service dhcpv6-relay upstream-interface eth2 address 2001:db8:100::4 + +Commit the changes and show results: + +.. code-block:: sh + + commit + show service dhcpv6-relay + listen-interface eth1 { + } + upstream-interface eth2 { + address 2001:db8:100::4 + } + +Show the current status of the DHCPv6 relay agent: + +.. code-block:: sh + + show dhcpv6 relay-agent status + +The DHCPv6 relay agent can be restarted with: + +.. code-block:: sh + + restart dhcpv6 relay-agent + +Additional parameters +^^^^^^^^^^^^^^^^^^^^^ + +DHCP relay agent options +************************ + +Set the maximum hop count before packets are discarded. Range 0...255, +default 10. + +* :code:`set service dhcp-relay relay-options hop-count 'count'` + +Set maximum size of DHCP packets including relay agent information. If a +DHCP packet size surpasses this value it will be forwarded without appending +relay agent information. Range 64...1400, default 576. + +* :code:`set service dhcp-relay relay-options max-size 'size'` + +Four policies for reforwarding DHCP packets exist: + +* **append:** The relay agent is allowed to append its own relay information + to a received DHCP packet, disregarding relay information already present in + the packet. + +* **discard:** Received packets which already contain relay information will + be discarded. + +* **forward:** All packets are forwarded, relay information already present + will be ignored. + +* **replace:** Relay information already present in a packet is stripped and + replaced with the router's own relay information set. + +* :code:`set service dhcp-relay relay-options relay-agents-packet 'policy'` + +DHCPv6 relay agent options +************************** + +Set maximum hop count before packets are discarded. Default: 10. + +* :code:`set service dhcpv6-relay max-hop-count 'count'` + +If this is set the relay agent will insert the interface ID. This option is +set automatically if more than one listening interfaces are in use. + +* :code:`set service dhcpv6-relay use-interface-id-option` |