What does ! do?

I'm going to guess that you are referring to IOS.

! is the IOS comment character.

Well sort of.

You can't actually use it to enter comments into the config

- unfortunately.

However anything you type after a "!" is ignored on the IOS comamnd line.

e.g.

conf t int fa 0/0 ip address 1.1.1.1 255.255.255.0 ! this bit after the "!" will be ignored.

! ip address 1.1.1.2 255.0.0.0 all of this line will be ignored ! this will be ignored too and will produce no error message

end

For some reason the config contains a number of lines that appear to be blank other then "!".

I use "!" to comment "paste" files that I intend to paste into router configs.

I really, really, really would find it VERY useful if the configs could actualy be decently commented.

Put the ! comments into your master copy. Copy the commented file to a file on devices that support files, and copy it directly to the startup config on devices that don't. Anything you copy directly into the startup config will be kept literally, and will not be interpreted until the configuration is parsed when you reload or power up or copy starting-config running-config or similiar, so to see the commented version, show start instead of show run .

Thanks for your help, SW