Can 'admin down' ports detect servers are connected?

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Apr 27th, 2009
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Imagine I have a switchport mode access configured, but it was placed as 'no shut'.

If someone claimed that they connected a server to such admin down port, is the status going to change?

Please let me know if I can assure that a device has been connected to a port which is 'admin down'. In this case is a server. cdp neighbor detection is disabled.


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Jon Marshall Mon, 04/27/2009 - 13:36
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If a switch port is shut down administratively then it doesn't matter what is connected into that port it will still say shutdown.


John Blakley Mon, 04/27/2009 - 13:40
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In addition to Jon's post, you said that the port was in "no shut." That means that the port is open for business, and it will come up when a host is attached. Admin down means that the port had bee administratively "shutdown" and you'll see that in the running-config.



news2010a Tue, 04/28/2009 - 07:44
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Oops. Sorry. I meant, the port is "shutdown". I meant to ask whether 'shut' ports can display status = connected on 'show int'.

cameron.moody Mon, 04/27/2009 - 18:54
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Further to this, one way to absolutely confirm would be to check the mac-address table (either for the specific port or for the MAC address on the server).

As other people have pointed out as well that "no shut" ports are live ports so there seems to be conflicting information.

The only time that I am aware of that a port status would change would be if it went into root-inconsistent state or err-disabled state etc, and had automatic recovery enabled. Even so the port would have to have been enabled (ie no shutdown).


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