+
+ The following destination MAC addresss will not be forwarded when this
+ option is enabled.
+ <dl>
+ <dt><code>01:80:c2:00:00:00</code></dt>
+ <dd>IEEE 802.1D Spanning Tree Protocol (STP).</dd>
+
+ <dt><code>01:80:c2:00:00:01</code></dt>
+ <dd>IEEE Pause frame.</dd>
+
+ <dt><code>01:80:c2:00:00:0<var>x</var></code></dt>
+ <dd>Other reserved protocols.</dd>
+
+ <dt><code>00:00:5e:00:01:<var>x</var><var>x</var></code></dt>
+ <dd> VRRP IPv4 virtual router MAC address. </dd>
+
+ <dt><code>00:00:5e:00:02:<var>x</var><var>x</var></code></dt>
+ <dd> VRRP IPv6 virtual router MAC address. </dd>
+
+ <dt><code>00:00:0c:07:ac:<var>x</var><var>x</var></code></dt>
+ <dd> HSRP Version 1. </dd>
+
+ <dt><code>00:00:0c:9f:f<var>x</var>:<var>x</var><var>x</var></code>
+ </dt>
+ <dd> HSRP Version 2. </dd>
+
+ <dt><code>00:07:b4:<var>x</var><var>x</var>:<var>x</var><var>x</var>:<var>x</var><var>x</var></code></dt>
+ <dd> GLBP. </dd>
+
+ <dt><code>01:00:0c:cc:cc:cc</code></dt>
+ <dd>
+ Cisco Discovery Protocol (CDP), VLAN Trunking Protocol (VTP),
+ Dynamic Trunking Protocol (DTP), Port Aggregation Protocol (PAgP),
+ and others.
+ </dd>
+
+ <dt><code>01:00:0c:cc:cc:cd</code></dt>
+ <dd>Cisco Shared Spanning Tree Protocol PVSTP+.</dd>
+
+ <dt><code>01:00:0c:cd:cd:cd</code></dt>
+ <dd>Cisco STP Uplink Fast.</dd>
+
+ <dt><code>01:00:0c:00:00:00</code></dt>
+ <dd>Cisco Inter Switch Link.</dd>
+ </dl>