I'm currently puzzled by why a switch works only when in unmanaged mode. If I enable Management mode, using default configuration, things break down. Here's the current situation:

                        VL60        TRUNK
    PC --------- SW1 ------- SW2 ------------ RT    <none>       <none>
  • SW1 is a Dell 2848 operating in unmanaged mode
  • SW2 is an Arista 7048-A running in managed mode

Given the above, everything WORKS. PC can reach its default gateway (RT) and anywhere else is properly routed.

However, if I change SW1 to managed mode, PC cannot ping RT.

I've factory reset SW1 and don't see anything out of the ordinary. Looking at status, the ports are up and forwarding. Any port on SW1 can ping any other port on itself. If I ping from PC, I can see the lights blinking on both SW1's incoming (from PC) and outgoing (to SW2) ports.

According to the Dell user manual for the 2848, here are the changes when in management mode:

  • Switch can be managed through the web interface.
  • Managed Mode LED is ON.
  • Device uses the saved running configuration (if it exists) or the default configuration.
  • The current running configuration is automatically saved to local storage. If the system is switched to unmanaged mode via the Managed Mode button, the system does not load the saved configuration, but it is still maintained in the device‚Äôs local storage.
  • From Managed mode, you can move to Unmanaged mode by pressing the Mode button on the device, or you can move to Secure mode using the web interface

None of which looks like the underlying cause... What am I missing?

  • How do you ping ports on SW1? Do they all have IP addresses? Since it's now managed, perhaps you can include the configuration in your post. – Ron Trunk Mar 4 '17 at 19:53
  • @RonTrunk I'm connecting two different systems in the same subnet and pinging each other. – Stanley Yu Mar 4 '17 at 19:56
  • My guess is there's a change in the VLAN tagging, but without seeing the configuration, there's no way to know. – Ron Trunk Mar 4 '17 at 19:58
  • I was also thinking in that direction, but wasn't sure. I'll get a configuration when I get the chance. – Stanley Yu Mar 4 '17 at 20:00
  • which IP did you assign to the switch in managed mode? are you sure there is no IP conflict? – Mr.lock Mar 5 '17 at 4:56

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