This is in all likelyhood "Safebrowsing by Google", which is a default service to run sites you visit past the servers of said company. https://www.google.com/

This is in all likelyhood "Safebrowsing by Google", which is a default service to run sites you visit past the servers of said company. https://www.google.com/transparencyreport/safebrowsing/diagnostic https://www.google.com/transparencyreport/safebrowsing/diagn... That would make you one of the 600 million people using that service, whether you realise it or not. Alas, other browsers use it too without any warning, although you can turn it off it is not easily discoverable: https://bugzilla.mozilla.org/show_bug.cgi?id=430741 https://bugzilla.mozilla.org/show_bug.cgi?id=430741 As suggested, add sb.google.com or whatever endpoint is used to /etc/hosts or HOSTS file.