Layer 2 Connectivity Issue.

Posted on 2009-05-13
Last Modified: 2012-05-06
I have a switch which won't allow me ping a management station.   This computer worked perfectly well before it was removed for a virus cleanup. Nothing has changed on the switch or switches!  It is a 3750 switch and both the management station the unreachable computer are all on the same vlan but on different switches across the network. The computer can reach the server with no problems. Port security was on but I had long removed it from the port, moved the computer to a different port, cleared port security from the port as well.  A different computer was used and still same results! When the computer is connected to some other location on the network(on a different access switch), it functions just fine!   I have done all but reset the switch. Does anyone have any idea of what I can possibly be looking at?
Question by:oliverwari
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LVL 21

Expert Comment

ID: 24374327
please provide running config from that switch
please also triple check ip settings of that pc (incorrect subnet mask?)
please also check mac address table of that particular port.

Author Comment

ID: 24374735
Subnet mask is correct.

LVL 21

Expert Comment

ID: 24375100
1/0/49 and 1/0/50 do have different vlans allowed (no 340 vlan on one of them)
I suppose those ports are used for uplinks/downlinks, so please check, that remote destination you are trying to reach is not behind that particular uplink port
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Author Comment

ID: 24375213
was trying to sanitize the is vlan 340 for trunks. The access switch has redundant connections to the distribution layer.
LVL 21

Accepted Solution

from_exp earned 500 total points
ID: 24375289
how do you archive redundancy? spanning-tree?
if yes, please try to ping from that pc your mgm station and try to search active down link port of the upper switch for that particular mac 552b

Author Comment

ID: 24375610
Thanks, you pointed me towards the right direction.
It was port security. Some dude had taken that computer and connected to a different switch and then brought it I had the mac address glued to a port on the management station switch.  I have cleared the port and everything is back to normal.

Author Closing Comment

ID: 31580913
I searched the mac and found it glued to a non trunk port on a different switch. Cleared and all is back up.. You are good.

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