Prtocol down on switch port

Unanswered Question
Apr 15th, 2008

I have a 1760 with a 4 port switch. Port 0/4 shows protocol down. Can anyone tell me how to trouble shoot? I have switched my servers from 0/3 to 0/4 and it is still down.

I have this problem too.
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lamav Tue, 04/15/2008 - 12:04

Hi, B:

Protocol down means that the layer 2 protocol running on your switch port is not synchronizing properly with the layer 2 protocol running on your server NIC.

Do the usual:

Ensure that all cables are properly connected.

Replace existing ethernet cables with KNOWN good ones

Check the speed and duplex settings. Make sure they are either hard-coded on both ends or set to auto-negotiate on both ends. If it's a gig port, just leave both ends set for auto, for starters.

Check the server NIC -- replace it if necessary.

Bounce the switch port

Reboot the switch

Smash switch with 5-pound hammer. :-)



Istvan_Rabai Tue, 04/15/2008 - 12:34

Hi Victor,

You are a funny guy, I like your style:)

However, you never know, he may take it word for word :)

Otherwise you're right.



lamav Tue, 04/15/2008 - 12:42


Istvan, what's up, buddy?? Long time!

I hope all is well.

I do read your posts and, as usual, I'm loving them! :-)

Good "talking" to you.


bmacbride Tue, 04/15/2008 - 12:54

The hammer actually worked! Just kidding. I did the old reboot the router an it came back up.


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