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Doc: Fix notes related to obsolete option

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Thanks to Julien Dessaux for the report.
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Ondrej Zajicek (work) 2018-08-07 14:46:24 +02:00
parent 5bd734317c
commit d33cf3f4c3
1 changed files with 4 additions and 16 deletions
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doc/bird.sgml
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@ -2848,14 +2848,6 @@ itself and BGP protocol is usually used for exporting aggregate routes. But the
Direct protocol is necessary for distance-vector protocols like RIP or Babel to Direct protocol is necessary for distance-vector protocols like RIP or Babel to
announce local networks. announce local networks.
<p>There is one notable case when you definitely want to use the direct protocol
-- running BIRD on BSD systems. Having high priority device routes for directly
connected networks from the direct protocol protects kernel device routes from
being overwritten or removed by IGP routes during some transient network
conditions, because a lower priority IGP route for the same network is not
exported to the kernel routing table. This is an issue on BSD systems only, as
on Linux systems BIRD cannot change non-BIRD route in the kernel routing table.
<p>There are just few configuration options for the Direct protocol: <p>There are just few configuration options for the Direct protocol:
<p><descrip> <p><descrip>
@ -2900,14 +2892,10 @@ interface) or whether an `alien' route has been added by someone else (depending
on the <cf/learn/ switch, such routes are either ignored or accepted to our on the <cf/learn/ switch, such routes are either ignored or accepted to our
table). table).
<p>Unfortunately, there is one thing that makes the routing table synchronization <p>Note that routes created by OS kernel itself, namely direct routes
a bit more complicated. In the kernel routing table there are also device routes representing IP subnets of associated interfaces, are not imported even with
for directly connected networks. These routes are usually managed by OS itself <cf/learn/ enabled. You can use <ref id="direct" name="Direct protocol"> to
(as a part of IP address configuration) and we don't want to touch that. They generate these direct routes.
are completely ignored during the scan of the kernel tables and also the export
of device routes from BIRD tables to kernel routing tables is restricted to
prevent accidental interference. This restriction can be disabled using
<cf/device routes/ switch.
<p>If your OS supports only a single routing table, you can configure only one <p>If your OS supports only a single routing table, you can configure only one
instance of the Kernel protocol. If it supports multiple tables (in order to instance of the Kernel protocol. If it supports multiple tables (in order to