Loopbacks on Cisco Switch 2950

Unanswered Question
Mar 8th, 2007

Hi,I am trying to configure a loopback on Cisco 2950 but I am getting invalid input detected. Its the weirdest thing - anyone any ideas?

Switch(config)#int loopback ?

<0-2147483647> Loopback interface number

Switch(config)#int loopback 0

RAP_PO_BelfastSwitch(config)#int loopback ?

<0-2147483647> Loopback interface number

% Invalid input detected at '^' marker.

I have this problem too.
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andrew.butterworth Thu, 03/08/2007 - 08:48

2950's are layer-2 only switches..... You can't create loopback interfaces on them.

Why would you want to anyway? there would be no way of routing to it.


maryodriscoll Thu, 03/08/2007 - 08:54

Didn't know it was a LAYER 2 device. It does have a vlan configured on it with an IP address allocated to it.

Richard Burts Thu, 03/08/2007 - 09:05


The VLAN interface on the 2950 is a virtual interface, much as the loopback is a virtual interface. A loopback interface would not provide any functionality not provided by the VLAN interface. The VLAN interface on the 2950 gives you IP access to the switch for management purposes. The 2950 can have only 1 active VLAN interface at a time.



maryodriscoll Thu, 03/08/2007 - 09:15

Ok fair enough, thanks. The reason I wanted to put on a different IP was purely because this device sits behind a customer firewall and there is no rule open for management through this fw.


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