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-rw-r--r--man/systemd.network.xml37
1 files changed, 18 insertions, 19 deletions
diff --git a/man/systemd.network.xml b/man/systemd.network.xml
index 5994869d97..e6dedb027d 100644
--- a/man/systemd.network.xml
+++ b/man/systemd.network.xml
@@ -363,29 +363,28 @@
</varlistentry>
<varlistentry>
<term><varname>IPForward=</varname></term>
- <listitem><para>Configures IP forwarding for the network
- interface. If enabled, incoming packets on the network
- interface will be forwarded to other interfaces according to
- the routing table. Takes either a boolean argument, or the
- values <literal>ipv4</literal> or <literal>ipv6</literal>,
- which only enables IP forwarding for the specified address
- family, or <literal>kernel</literal>, which preserves existing sysctl settings.
- This controls the
- <filename>net.ipv4.conf.&lt;interface&gt;.forwarding</filename>
- and
- <filename>net.ipv6.conf.&lt;interface&gt;.forwarding</filename>
- sysctl options of the network interface (see <ulink
+ <listitem><para>Configures IP packet forwarding for the
+ system. If enabled, incoming packets on any network
+ interface will be forwarded to any other interfaces
+ according to the routing table. Takes either a boolean
+ argument, or the values <literal>ipv4</literal> or
+ <literal>ipv6</literal>, which only enable IP packet
+ forwarding for the specified address family. This controls
+ the <filename>net.ipv4.ip_forward</filename> and
+ <filename>net.ipv6.conf.all.forwarding</filename> sysctl
+ options of the network interface (see <ulink
url="https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">ip-sysctl.txt</ulink>
for details about sysctl options). Defaults to
<literal>no</literal>.</para>
- <para>Note: unless this option is turned on, or set to <literal>kernel</literal>,
- no IP forwarding is done on this interface, even if this is
- globally turned on in the kernel, with the
- <filename>net.ipv4.ip_forward</filename>,
- <filename>net.ipv4.conf.all.forwarding</filename>, and
- <filename>net.ipv6.conf.all.forwarding</filename> sysctl
- options.</para>
+ <para>Note: this setting controls a global kernel option,
+ and does so one way only: if a network that has this setting
+ enabled is set up the global setting is turned on. However,
+ it is never turned off again, even after all networks with
+ this setting enabled are shut down again.</para>
+
+ <para>To allow IP packet forwarding only between specific
+ network interfaces use a firewall.</para>
</listitem>
</varlistentry>
<varlistentry>