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spanning tree

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Super Advisor

spanning tree


normally the router or switch has STP spanning tree enabled by default.

I have 3 questions:

1.) if I enable portfast on some ports, that means I will disable spanning tree on these ports ?

2.) should I enable or disable spanning-tree
on trunking ports between Layer 3 Router and Layer 2 Switch ?

3.) when should I use portfast and when not ?

kind regards
Carsten M
Regular Advisor

Re: spanning tree

Hi Chris!

1) No, the port goes fast to forward, that can occour in short and strong loops, but spt works after that and blocked the port.

2)Enable it

3)Enable, on ports to to a single device
Disable, all others
That i think is the best solution
Uffe Gavnholt_1
Honored Contributor

Re: spanning tree

I just have a comment to #3 - portfast should en general be enabled on all ports leading to non-stp devices.

Super Advisor

Re: spanning tree

1.) what's single device or non-single device ?

2.) what about firewalls ?
is it a firewall non-single device ?

3.) should I enable st on the switch ports connected to the firewalls ?

4.) should I generally enable spanning-tree
on all DELL switches ports connected to the clients & servers in a 200 user company ?
we have ca. 30 servers and use CISCO VPN to the branches.