Setting an automated trap

How many hits is too many?

[too much information]

I set up a trap on a site to ban any IP that hits a page more than 5 times in a second. (This has happened more than once and I really don't understand why)

Anyhow, I have had visitors that hit a page 15 times or so in a minute for a few minutes and although they are dynamically generated there is no reason for any normal person to do this.

Does anyone have a suggestion on how many hits per min. should be a trigger to be banned? I would rather then download a 403 rather than my image heavy homepage.

[ronburk]

You probably already know, but of course:

IP!= user

It's very common for many people to be using the same IP address at the exact same time (due to NAT), at least so far as any web server can detect.

[too much information]

Yea, I'm aware of that but what I don't need is the 500+ hits in 20 min that some users put on the homepage of my site.

Is there some reason that a machine would do this without the user knowing?