I don't have samsung galaxy S5 but someone with that phone signed in to my account. The IP address was the same as mine… Do more people share the same IP even if they're not using the same wifi?
Added (1). My gmail shows me recent devices that logged in to my account. I know that internal IPs start with 192. Etc but what about external IP, if they have the same external IP as me and logged in my account with that, does that mean the hacker was in my house?
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Someone signed into my gmail from an unknown device?