I have two Cisco 2950 switches connected with a Dell 7810 machine to provide network redundancy.

The machine is equipped with one built in (On Mother Board) Ethernet port and with a dual port NIC “Intel X520-T2 Dual Port 10GbE”. Here I have been facing problem in communicating the dual port NIC with the switch. The built in port is working fine in all cases.

From the adapter settings/properties when the “Speed” of NIC is selected to “Auto Negotiate” it didn’t communicate with the switch. For that switch port is additionally configured and adjust the switch port Speed to “Auto”, after both adjustments a healthy communication is established.

Here can anyone be kind enough to let me know that why the communication didn’t established when only configured from adapter (NIC) settings/properties (Why the switch port configuration need is felt when the adapter is been configured to “Auto”)?

One more thing, as per my understanding the CISCO has now stopped the support for 2950. So if the access to the switch port configuration is not available through Internet Explorer, what should be the alternate to resolve the problem (keeping in mind the switches and machine are in always running mode)?

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1 Answer 1


The way it works is that if one side is set to Auto, the other side needs to be set to Auto for things to work correctly.

If one side is set to fixed speed and duplex, the other side can detect the speed, but will default to the duplex for the speed (10/100 Mb is half, 1 Gb is full, and 10 Gb only has full). The mismatched duplex causes all kinds of problems on the link.

Cisco has a document, Troubleshooting Cisco Catalyst Switches to NIC Compatibility Issues, which explains this.

The 2950 has been EoL for a long time. That doesn't change the way which it can be configured, so I'm not sure about your last question. Most of the time, Cisco devices will be configured with something like telnet or SSH using the CLI. The console port can also be used for configuration when someone is on-site with the switch.

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