Items Rating-How to block a bot

I have some sort of bot that comes to my site and runs through a bunch of items rating each a 1 star
I have tried stopping bots from entering Item Ratings using Robots.txt file but still it keeps happening
I will attach an email showing all the ratings i received in just a minute or so
Is there a way to add a time out somehow so that if an item is rated another cannot be rated for like 20 seconds?
Or is there a way to make the Items rating module just disregard ALL ratings that are a 1 star...
Im going in with the bulk edit tool to remove them but its become a weekly task which I wish i didnt have to do
I suppose i could ban the IP of the bot...but in the past banning IPs can present problems where entire groups of IP's get banned...I would prefer to just remove the Items rating from items before banning IPs
Thanks
updated by @derrickhand300: 05/05/18 08:36:35AM

Just ban the specific IP address, not a range of addresses.

Why not close their account or stop them from rating? Or do you allow unlogged in users to rate items?


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¯\_(ツ)_/¯ Education, learning resources, TEL, AR/VR/MR, CC licensed content, panoramas, interactive narrative, sectional modules (like jrDocs), lunch at Uni of Bristol. Get in touch if you share my current interests or can suggest better :)

Yes on my site i am the only logged in users...I allow unlogged in users to rate
My site has 1 member- me
everyone else is a visitor

If not logged in users can rate, bots (and everyone else) can rate anything as "1" unless you can ban their IP address one by one.

I guess you could write a custom module to make any "1" rating a "2", or to not count it at all. But does that really make sense? Do you know of any other websites which allow ratings by not logged in users?


--
¯\_(ツ)_/¯ Education, learning resources, TEL, AR/VR/MR, CC licensed content, panoramas, interactive narrative, sectional modules (like jrDocs), lunch at Uni of Bristol. Get in touch if you share my current interests or can suggest better :)