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New Member

Deleting a virtual interface

There is a debate among our engineers on the proper command to delete a virtual interface on an MSFC. Which command is correct and why?

delete interface vlanxxx

or

no interface vlanxxx

There's a dinner riding on this one!

1 ACCEPTED SOLUTION

Accepted Solutions
Silver

Re: Deleting a virtual interface

delete interface ??

Never heard of it. DELETE command is an EXEC command used for file system operation (e.g. delete a certain file) but certainly not deleting interfaces.

I checked all of our 3560,3750,c6506-native, and c6506-hybrid with MSFC. All results are negative. Like this:

msfc_hra_old(config)#del?

% Unrecognized command

c6506_hra_1(config)#del?

% Unrecognized command

And so on.

That's what I expected btw, because again, I have never heard of the command.

There is a command that is called "DEFAULT" maybe that's the one you are thinking of. This command returns an interface to a default state.

NO INTERFACE command deletes a virtual interface.

When reenabling virtual interface (not SVI) some configuration may reappear. Therefore the cleanest way to delete a virtual interface is:

default interface fa0/0.1

no interface fa0/0.1

SVI could be deleted using "no" command without the need to use "default" command.

As to your question. IF the command does exist on some special version of IOS, it surely doesn't exist anywhere else. Therefore using a special command, that is not documented is not a good idea in an routine environment.

5 REPLIES
Hall of Fame Super Bronze

Re: Deleting a virtual interface

The latter

no interface vlanxxx

.........

Rack1SW2#show ip int bri | ex una

Interface IP-Address OK? Method Status Protocol

Vlan28 183.1.28.8 YES manual up up

Rack1SW2(config)#no interface vlan 28

Rack1SW2(config)#do show ip int bri | ex una

Interface IP-Address OK? Method Status Protocol

New Member

Re: Deleting a virtual interface

Is there a reason why the delete interface command should not be used?

Silver

Re: Deleting a virtual interface

delete interface ??

Never heard of it. DELETE command is an EXEC command used for file system operation (e.g. delete a certain file) but certainly not deleting interfaces.

I checked all of our 3560,3750,c6506-native, and c6506-hybrid with MSFC. All results are negative. Like this:

msfc_hra_old(config)#del?

% Unrecognized command

c6506_hra_1(config)#del?

% Unrecognized command

And so on.

That's what I expected btw, because again, I have never heard of the command.

There is a command that is called "DEFAULT" maybe that's the one you are thinking of. This command returns an interface to a default state.

NO INTERFACE command deletes a virtual interface.

When reenabling virtual interface (not SVI) some configuration may reappear. Therefore the cleanest way to delete a virtual interface is:

default interface fa0/0.1

no interface fa0/0.1

SVI could be deleted using "no" command without the need to use "default" command.

As to your question. IF the command does exist on some special version of IOS, it surely doesn't exist anywhere else. Therefore using a special command, that is not documented is not a good idea in an routine environment.

New Member

Re: Deleting a virtual interface

Your correct. I meant to say default.

Thank you for clearing this up.

Silver

Re: Deleting a virtual interface

So... have you won a dinner? :)

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