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Console port question


I am configuring an 1841 and had a look at the access-class that one can tie to the console port.

However the access-class is an IP Based ACL, which makes me wonder how it is meant to block a serial connection? (ie I plug my console cable from my pc into the console port of the router)

Also can someone please point me in the direction of Cisco documentation that can give me an in depth description of each console command?

Many Thanks


Cisco Employee

Re: Console port question

Hello Willem,

The "access-class in" command is indeed intended to control an IP-based management connection, such as Telnet or SSH. As such, it can only be used reasonably on "line vty", not on "line con 0".

The physical console is most often protected by a password or by a combination of username and password. In extreme cases, it can set up to not to start the command line interface but that would be quite an inconvenient configuration choice if something goes wrong.

The Cisco documentation on their website is very extensive. Regarding the IOS, I suggest starting with this link:

Note a few links in that page. The "Master Index" leads to a complete list of all available commands and links to their respective command reference (see below).

Then there are Command References. These documents describe each command in detail, together with its parameters and their meaning.

Then, there are Configuration Guides. These are guides describing a particular technology and ways to configure it.

Regarding the console settings, I suggest starting with the Configuration Fundamentals Guide at

It gets some time to get used to the style and the organization of the Cisco documentation but once you get into it, you'll enjoy it very much.

Best regards,


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