ected to a single host. Connecting hubs, concentrators, switches, bridges, etc. to this interface when portfast is enabled, can cause temporary bridging loops. Use with CAUTION %Portfast has been configured on FastEtherneto/20 but will only have effect when the interface is in a non-trunking mode. Additional Spanning Tree Features To disable PortFast on an interface in IOS, simply negate the command. There is no fanfare when disabling PortFast: Cat-3550(config-if)#no spanning-tree portfast Cat-3550(config-if)# On a CatOS switch, the command to enable PortFast is set spantree portfast <mod/ port> enable. Executing this command will also result in a nice message about the dangers of PortFast: Catos-6509: (enable)s spantree portfast 3/10 enable Warning: Connecting Layer 2 devices to a fast start port can cause temporary spanning tree loops. Use with caution. Spantree port 3/10 fast start enabled. To disable PortFast, use the same command with disable instead of enable: Catos-6509: (enable)set spantree portfast 3/10 disable Spantree port 3/10 fast start disabled. On Nexus, PortFast is configured using the spanning-tree port type edge interface command: NX-5K-1 .(config-if)# spanning-tree port type edge Warning: Edge port type (portfast) should only be enabled on ports connected to a single host. Connecting hubs, concentrators, switches, bridges, etc... to this interface when edge port type (portfast) is enabled, can cause temporary bridging loops. Use with CAUTION Edge Port Type (Portfast) has been configured on Ethernet100/1/12 but will only have effect when the interface is in a non-trunking mode. For servers that require trunks, a special type of PortFast is offered. To configure a trunk to a server with PortFast, use the spanning-tree port type edge trunk interface command: NX-5K-1(config-if)# spanning-tree port type edge trunk Warning: Edge port type (portfast) should only be enabled on ports connected to a single host. Connecting hubs, concentrators, switches, bridges, etc. this interface when edge port type (p