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authorRobert Göhler <github@ghlr.de>2022-01-17 12:47:31 +0100
committerGitHub <noreply@github.com>2022-01-17 12:47:31 +0100
commit09f087740844b447085be46a37728c896e6c1544 (patch)
treeca6d3a19ae67b2b0e20425f472c21e546a3d5cfe /docs/configuration/interfaces/pppoe.rst
parent7ee5c8a55b56706a42a48ec00681c7992f7f1491 (diff)
parent83f983ceef5ff683ac25855d6dfae96a6af1d05d (diff)
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Merge pull request #697 from mrbuk/master
Fix description of 'adjust-mss' option
Diffstat (limited to 'docs/configuration/interfaces/pppoe.rst')
-rw-r--r--docs/configuration/interfaces/pppoe.rst59
1 files changed, 59 insertions, 0 deletions
diff --git a/docs/configuration/interfaces/pppoe.rst b/docs/configuration/interfaces/pppoe.rst
index 41f22ed6..4a31efc5 100644
--- a/docs/configuration/interfaces/pppoe.rst
+++ b/docs/configuration/interfaces/pppoe.rst
@@ -177,6 +177,44 @@ PPPoE options
PPPoE connection must be established over a physical interface. Interfaces
can be regular Ethernet interfaces, VIFs or bonding interfaces/VIFs.
+.. cfgcmd:: set interfaces pppoe <interface> ip adjust-mss <mss | clamp-mss-to-pmtu>
+
+ As Internet wide PMTU discovery rarely works, we sometimes need to clamp our
+ TCP MSS value to a specific value. This is a field in the TCP options part of
+ a SYN packet. By setting the MSS value, you are telling the remote side
+ unequivocally 'do not try to send me packets bigger than this value'.
+
+ .. note:: This command was introduced in VyOS 1.4 - it was previously called:
+ ``set firewall options interface <name> adjust-mss <value>``
+
+ .. hint:: MSS value = MTU - 20 (IP header) - 20 (TCP header), resulting in
+ 1452 bytes on a 1492 byte MTU.
+
+ Instead of a numerical MSS value `clamp-mss-to-pmtu` can be used to
+ automatically set the proper value.
+
+.. cfgcmd:: set interfaces pppoe <interface> ip disable-forwarding
+
+ Configure interface-specific Host/Router behaviour. If set, the interface will
+ switch to host mode and IPv6 forwarding will be disabled on this interface.
+
+.. cfgcmd:: set interfaces pppoe <interface> ip source-validation <strict | loose | disable>
+
+ Enable policy for source validation by reversed path, as specified in
+ :rfc:`3704`. Current recommended practice in :rfc:`3704` is to enable strict
+ mode to prevent IP spoofing from DDos attacks. If using asymmetric routing
+ or other complicated routing, then loose mode is recommended.
+
+ - strict: Each incoming packet is tested against the FIB and if the interface
+ is not the best reverse path the packet check will fail. By default failed
+ packets are discarded.
+
+ - loose: Each incoming packet's source address is also tested against the FIB
+ and if the source address is not reachable via any interface the packet
+ check will fail.
+
+ - disable: No source validation
+
IPv6
----
@@ -185,6 +223,27 @@ IPv6
Use this command to enable acquisition of IPv6 address using stateless
autoconfig (SLAAC).
+.. cfgcmd:: set interfaces pppoe <interface> ipv6 adjust-mss <mss | clamp-mss-to-pmtu>
+
+ As Internet wide PMTU discovery rarely works, we sometimes need to clamp our
+ TCP MSS value to a specific value. This is a field in the TCP options part of
+ a SYN packet. By setting the MSS value, you are telling the remote side
+ unequivocally 'do not try to send me packets bigger than this value'.
+
+ .. note:: This command was introduced in VyOS 1.4 - it was previously called:
+ ``set firewall options interface <name> adjust-mss <value>``
+
+ .. hint:: MSS value = MTU - 20 (IP header) - 20 (TCP header), resulting in
+ 1452 bytes on a 1492 byte MTU.
+
+ Instead of a numerical MSS value `clamp-mss-to-pmtu` can be used to
+ automatically set the proper value.
+
+.. cfgcmd:: set interfaces pppoe <interface> ipv6 disable-forwarding
+
+ Configure interface-specific Host/Router behaviour. If set, the interface will
+ switch to host mode and IPv6 forwarding will be disabled on this interface.
+
.. cmdinclude:: /_include/interface-dhcpv6-prefix-delegation.txt
:var0: pppoe
:var1: pppoe0