We are having an issue on a 2960 switch when we add a new device to the switch (in this case a printer), the rest of the devices drop.
They only come back if we reboot the switch.
Are you sure the printer is not connected to a different switch and connected to the 2960? Sounds like you have a broadcast storm happening.
Try this command in the interface where this printer is connected "spanning-tree bpduguard enable". This command will shut down (err-disable) the port if the switch can "hear" BPDU coming into the said port. You can re-enable the port by issuing the commands "shutdown" followed by a "no shutdown".
Does your 2960 have a Gig port to do some trivial testing? If it does, connect the printer to the Gig port and issue the following commands:
1. interface Gig0/1;
2. media rj
3. end (this command will take you out of configuration mode)
4. test cable tdr int Gig0/1
5. Wait for about 5 to 7 seconds
6. sh cable tdr int Gig0/1
7. conf t
8. int Gig0/1
9. media auto
Post the output for the "sh cable tdr int Gig0/1" command.
Can you tell us if we see the mac addresses of the desktops in the CAM after you add this device?
What VLAN does the printer to belong to? What VLAN are the desktops in?
Also, can you share the output of the following when the issue occurs:
- sh spann de ac | i exe|Number of top|from
- Config of port where the printer is connected