diff --git a/source/manual/vpnet.rst b/source/manual/vpnet.rst index 81b42aa..4d96e65 100644 --- a/source/manual/vpnet.rst +++ b/source/manual/vpnet.rst @@ -296,6 +296,19 @@ In which case the following tunables need to be changed: * :code:`net.inet.rss.bits` = **X** <-- see :doc:`rss ` document. +................................. +Miscellaneous variables +................................. + +Path MTU Discovery +-------------------------- + +When trying to enforce path mtu discovery (`PMTU `__), you need to make +sure packets leave the network with the :code:`DF` set. The kernel offers a tunable :code:`net.inet.ipsec.dfbit` which +offers 3 options, :code:`0`, clear the bit on packets leaving the firewall (default), :code:`1`, set the DF bit or :code:`2` +to copy the bit from the inner header. + + ................................. Diagnostics .................................