Please advise on the following question:

With 2 Cisco 2960G switches connected as in the diagram:

enter image description here

STP is not used.

How could the switches be configured in such a way that all the traffic HOST<->SERVER will go like HOST->SW1->SW2->SW1->SERVER as in the picture, but not HOST->SW1->SERVER.

Is there a way to block "internal" ports on SW1?

  • 3
    First, tell us why you want to subvert the normal (fast) switch path?
    – Ricky
    Oct 5, 2015 at 20:13

2 Answers 2


To meet this requirement, you can configure switch ports as protected ports (also referred to as private VLAN edge ports). Protected ports do not forward any traffic to protected ports on the same switchso configure port attached to host and server as protected port . This means that all traffic passing between protected ports be forwarded through a Layer 3 device. so that just configure vlan 24 as a interface vlan on SW2

NOTE Protected ports can forward any type of traffic to nonprotected ports, and they forward as usual to all ports on other switches. Dynamically learnt addresses are not retained if the switch is reloaded.

  • Thank you. That is working pretty well, at least there is no more loop, only one thing is that there is latency fluctuation, sometimes 60-70% of ping loss... Oct 6, 2015 at 12:10
  • it is very clear you do switch loop but it seams like you need to know about this case itself so i don't proceed in advice you about don't doing switch loop or at lest configure spanning tree , i think protected port is the only way to do what you need as it is
    – Gadeliow
    Oct 6, 2015 at 12:16

Traffic direction with only one way

This is your configuration. You need to configure the host and one port of the switch that connect to the host one the same vlan(23). Then, on the other switch, the 2 ports need to be on another same vlan(24). Finally, do the same with the other port and the server port(vlan25).

All port must be configured like ACCESS-PORTS. Remember that

  • Sorry, I didn't mentioned that VLANs ID should be the same on all network "chains"... That's why it wouldn't work for me. Anyway thank you! Oct 6, 2015 at 12:08

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