Someone has been making requests on one my sites.The whole access log is filled with request for directories that don't exist, they have been doing all day enough times to pull off 500 megabytes of bandwidth. I of course banned them blocking there IP in iptables ( Firewall ). Not this this really going to hurt me. I have terabytes of bandwidth. lol But its just annoying why would some idiot do something like that?
They could be looking for vulnerabilities in your website, using a program like Acunetix Web scanner ... So just make sure is everything secure because someone may try targeting you, or looking for a simple way to exploit your site.
~ 500mb of 404's would take many requests. Doesn't sound like a DDOS attempt as it would be more useful to request real pages. Where is the IP located? Are there exploit attempts in the noise or just crawling of random directories.