When altering the browser-tag, you're always welcomed as Googlebot (if you changed the tag to googlebot's) - it does not matter which IP you have.
For example at my localhost, I have 127.0.0.1 and the software greeted my with "Logout [ Googlebot ]".

Furthermore, in ACP -> Bot-Settings you are told to seperate IPs with an apostrophe. But if you do so, you'll receive an error while saving that settings.
>> The IP addresses you supplied were invalid or the hostname could not be resolved.