03-14-2007 04:37 AM - edited 03-03-2019 04:09 PM
Hi
My company has requested me to install a switch on a WAN link.
They requested I configure a loopback address.
I configured the switch vlan1 with an ip/mask and no shut it.
The WAN link goes through the switch no problem.
When I configure an Loopback addrees ie
switch#config t
switch(config)#interface loopback 1
switch(config)#int loopback 1
^
% Invalid input detected at '^' marker.
However if you question mark int ?
switch(config)#int ?
looback is shown as a vaild command.
any one have any ideas?
03-14-2007 04:38 AM
The ^ should be under Loopack
03-14-2007 05:16 AM
Hi Friend,
2950 is a pure layer 2 switch so it does not need a loopback interface. The command will be present because 2950 works on basic IOS train which have this command but 2950 platform does not support this command.
HTH
Ankur
*Please rate helpfull post
03-14-2007 08:39 AM
Richard
Ankur gives a good explanation that the 2950 as a layer 2 switch does not support loopback interfaces and that loopback does show in help because it works out of a standard template for help in IOS.
In addition it may be helpful to point out that layer 2 switches can have only a single active virtual interface with an IP address. You indicate that you have configured VLAN 1 and given it an IP address. If you were to configure another VLAN (perhaps VLAN 2) and give it an IP address your would find that VLAN 1 shuts down. There can be only 1 active virtual interface with an IP address on the layer 2 switch.
HTH
Rick
03-14-2007 09:58 AM
Thanks for the info
09-07-2008 07:50 PM
Hello ankur,
I am also have the same problem.
I wonder why i can input the command interface loopback 0 on ios c2950-i6q4l2-mz.121-9.EA1.bin
but not on c2950-i6q4l2-mz.121-12c.EA1.bin
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