diff --git a/man/systemd.netdev.xml b/man/systemd.netdev.xml
index 8ccc7c1a5a0..a44018cad6d 100644
--- a/man/systemd.netdev.xml
+++ b/man/systemd.netdev.xml
@@ -1008,7 +1008,8 @@
         <term><varname>FooOverUDP=</varname></term>
         <listitem>
           <para>Takes a boolean. Specifies whether <varname>FooOverUDP=</varname> tunnel is to be configured.
-          Defaults to false. For more detail information see
+          Defaults to false. This takes effects only for IPIP, SIT, GRE, and GRETAP tunnels.
+          For more detail information see
           <ulink url="https://lwn.net/Articles/614348">Foo over UDP</ulink></para>
         </listitem>
       </varlistentry>
@@ -1016,7 +1017,7 @@
         <term><varname>FOUDestinationPort=</varname></term>
         <listitem>
           <para>This setting specifies the UDP destination port for encapsulation.
-          This field is mandatory and is not set by default.</para>
+          This field is mandatory when <varname>FooOverUDP=yes</varname>, and is not set by default.</para>
         </listitem>
       </varlistentry>
       <varlistentry>
@@ -1029,7 +1030,7 @@
       <varlistentry>
         <term><varname>Encapsulation=</varname></term>
         <listitem>
-          <para>Accepts the same key as <literal>[FooOverUDP]</literal></para>
+          <para>Accepts the same key as in the <literal>[FooOverUDP]</literal> section.</para>
         </listitem>
       </varlistentry>
       <varlistentry>
@@ -1074,13 +1075,6 @@
     following keys:</para>
 
     <variablelist class='network-directives'>
-      <varlistentry>
-        <term><varname>Protocol=</varname></term>
-        <listitem>
-          <para>The <varname>Protocol=</varname> specifies the protocol number of the
-          packets arriving at the UDP port. This field is mandatory and is not set by default. Valid range is 1-255.</para>
-        </listitem>
-      </varlistentry>
       <varlistentry>
         <term><varname>Encapsulation=</varname></term>
         <listitem>
@@ -1103,7 +1097,17 @@
           for delivery to the real destination. This option is mandatory.</para>
         </listitem>
         </varlistentry>
-      </variablelist>
+      <varlistentry>
+        <term><varname>Protocol=</varname></term>
+        <listitem>
+          <para>The <varname>Protocol=</varname> specifies the protocol number of the packets arriving
+          at the UDP port. When <varname>Encapsulation=FooOverUDP</varname>, this field is mandatory
+          and is not set by default. Takes an IP protocol name such as <literal>gre</literal> or
+          <literal>ipip</literal>, or an integer within the range 1-255. When
+          <varname>Encapsulation=GenericUDPEncapsulation</varname>, this must not be specified.</para>
+        </listitem>
+      </varlistentry>
+    </variablelist>
   </refsect1>
   <refsect1>
     <title>[Peer] Section Options</title>