D-Link DES-3326 User Manual page 63

24-port NWay Ethernet Switch User's Guide
Figure 5-3. STP Port State Transitions
When you enable STP, every port on every switch in the network
goes through the blocking state and then transitions through the
states of listening and learning at power up. If properly
configured, each port stabilizes to the forwarding or blocking
state.
No packets (except BPDUs) are forwarded from, or received by,
STP enabled ports until the forwarding state is enabled for that
port.
Default Spanning-Tree Configuration
Switch Management and Operating Concepts
47