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Cat 3650 config - line vty 0 15 split

Probably a simple question. Why are vty terminals 0 through 4 split from 5 through 15? Example...

line vty 0 4

transport preferred none

transport input telnet

transport output none

line vty 5 15

transport preferred none

transport input telnet

transport output none

Why isnt there a single entry of the form...

line vty 0 15

transport preferred none

transport input telnet

transport output none

What is special about vty's 0 to 4?

1 ACCEPTED SOLUTION

Accepted Solutions

Re: Cat 3650 config - line vty 0 15 split

Hi,

historically there have been line vty 0 to 4 in IOS. I suppose for downward compatibility the config has been split. Assume you downgrade to an IOS not supporting vty lines above 4. Then the command "line vty 0 15" would produce an error message and NO vty would be configured at all, most likely resulting in no remote access to the device.

So "line vty 0 4" will achieve remote access even if downgrading to an IOS not supporting vty up to 15.

Hope this helps! Please rate all posts.

Regards, Martin

2 REPLIES

Re: Cat 3650 config - line vty 0 15 split

Hi,

historically there have been line vty 0 to 4 in IOS. I suppose for downward compatibility the config has been split. Assume you downgrade to an IOS not supporting vty lines above 4. Then the command "line vty 0 15" would produce an error message and NO vty would be configured at all, most likely resulting in no remote access to the device.

So "line vty 0 4" will achieve remote access even if downgrading to an IOS not supporting vty up to 15.

Hope this helps! Please rate all posts.

Regards, Martin

New Member

Re: Cat 3650 config - line vty 0 15 split

Thanks, i figured it would be for backward compatibility but i thought it best to check and make sure. Thanks for the quick reply.

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