I can't think of anything in the wild. You could get far with setting up some webhooks and sending events to IFTTT. Having it self hosted, in the end its a mat

I can't think of anything in the wild. You could get far with setting up some webhooks and sending events to IFTTT. Having it self hosted, in the end its a matter of logging some information about users requesting access in to a database, having a UI to display data from said database and having some small automation to add the IP to a whitelist / blacklist.