Site scan

This morning, I look through the statistics and see that the site was actively checked by some bot. And it lasted about an hour with an interval of 5 seconds. I notice that at first this bot wandered through the links posted on the site (similar to search bots). But then I see a stunning picture - the bot followed the links that are not on my site. Moreover - these are links posted on other sites, which I visited for an indefinite time ago. And without domains. Those. the bot was trying to find pages of other sites on my server ...



I thought maybe some system that checks if I have not stolen content from someone else’s site ... But, as I said, there were a lot of sites whose links were checked - it means the system does not belong to any of them ... I checked according to summary statistics - ip was not never. I watched by WhoIs - also nothing remarkable. It remains only to guess what it is. Maybe something related to the browser, or one of the transit servers, or an eye of the special services, or something else ...

Did anyone have that?