Has the network of a recently used machine been attacked? Or has the IP become shared?

Can you describe any symptoms/issues you have encountered to make you think this?

Hey there! There are a few different possibilities, but we really can't look into it without more information. I'd recommend reviewing our Asking Better Questions post for more information on what we might be looking for. I can confirm each Linode has its own IP and does not share that IP address with another Linode.