What is spanning-tree Bpduguard?
BPDU Guard feature is used to protect the Layer 2 Spanning Tree Protocol (STP) Topology from BPDU related attacks. When a BPDU Guard enabled port receive BPDU from the connected device, BPDU Guard disables the port and the port state is changed to Errdisable state.
Is BPDU guard enabled by default?
By default, BPDU guard is disabled. Enter interface configuration mode, and specify the interface connected to an end station. When you globally enable BPDU filtering on Port Fast-enabled ports, it prevents ports that are in a Port Fast-operational state from sending or receiving BPDUs.
Is STP by default configure in Cisco switch?
By default, RSTP is the mode enabled on every port of a switch. It prevents Layer 2 loops in a network.
Does STP use BPDU?
All spanning-tree protocols use a special type of frame called bridge protocol data units (BPDUs) to communicate with each other. STP processes on bridges exchange BPDUs to determine the LAN topology, decide the root bridge, stop forwarding on some ports, and so on.
Why Portfast is used?
The PortFast feature is introduced to avoid network connectivity issues. These issues are caused by delays in STP enabled ports moving from blocking-state to forwarding-state after transitioning from the listening and learning states.
What is spanning-tree Portfast default?
The spanning-tree portfast default global configuration mode command enables PortFast on all non-trunking interfaces. To configure BPDU guard on a Layer 2 access port, use the spanning-tree bpduguard enable interface configuration mode command, as shown in Example 3-6.
Is STP required to be configured when there is only one switch?
Q: If a network has only one switch, does STP take place? A: Yes. STP operations occur as they normally would, although no topology is discovered or built due to there being only a single switch. The switch will send BPDU’s out any connected ports but connected devices that aren’t switches will drop/ignore the BPDU’s.
What is the purpose of STP in a switched LAN?
The Spanning Tree Protocol (STP) is responsible for identifying links in the network and shutting down the redundant ones, preventing possible network loops. In order to do so, all switches in the network exchange BPDU messages between them to agree upon the root bridge.
Is BPDUs a broadcast?
Bridge Protocol Data Units (BPDUs) are messages exchanged between the switches inside an interconnected redundant Local Area Network (LAN). The basic purpose of the Bridge Protocol Data Units (BPDUs) and the Spanning Tree Algorithm (STA) is to avoid Layer 2 Switching loops and Broadcast storms.
Who will send Bpdu?
Bridge Protocol Data Units (BPDUs) are frames that contain information about the spanning tree protocol (STP). A switch sends BPDUs using a unique source MAC address from its origin port to a multicast address with destination MAC (01:80:C2:00:00:00, or 01:00:0C:CC:CC:CD for Cisco proprietary Per VLAN Spanning Tree).
How to enable BPDU guard?
configure terminal. Enter global configuration mode.
Does portfast disable spanning-tree?
Does portfast disable Spanning-Tree? A common misunderstanding among Cisco students is that portfast disables spanning-tree on a certain interface. This is not correct however…if you enable portfast on an interface then it will jump to the forwarding state of spanning-tree. We still run spanning-tree on the interface!
What is BPDU filter?
BPDUs are the messages exchanged between switches to calculate the spanning tree topology. BPDU filter is a feature used to filter sending or receiving BPDUs on a switchport.