63. Configure Portfast and BPDU Guard
Problem with STP
STP is enabled on all interfaces by default
problem is when we connect end devices as they needed to wait for 30 seconds (STP)
and 15 seconds (RSTP) before the interface will be in forwarding state (usable)
solution is portfast
Portfast
transitions immediately from a Blocking State into Forwarding State
should only be configured on interfaces where end devices are connected.
but, what if a switch is connected to a portfast enabled interface?
*solution: BPDU Guard
= it will automatically disable the interface when it receives BPDU
= state of the interface is "errdisabled"
= portfast and BPDU Guard are partner to be configured on interfaces
where end devices are connected
Best Pratice:
configure only portfast on interfaces where end devices are connected with BPDU Guard
Sw1:
conf t
int fa 0/2
spanning-tree portfast
spanning-tree bpduguard enable
exit