Is this a good way to limit posts per minute?

[Prodigal Son]

I have a comments section (doesn't require registration). And to limit posts to max 1 per minute, I have the users IP recorded and the time of posting. Each time when they post I match the IP and grab the timestamp of their post and add 60 seconds to it. If it's less than or equal to time() they can post a message, otherwise a warning says they need to wait a certain amount of time before they can post again. Not sure if this is the best way to do it, but that's how I did it. Also I noticed that I can just change my computer time and I can bypass this restriction. My assumption is that I am using my localhost so I can do this. If I'm on a web server a visitor couldn't do that right?

[DeanWhitehouse]

use date() to get the time

[Prodigal Son]

use date() to get the time

Yea if they can change the computer date/time wouldn't that also bypass it if you have date? Don't have a webserver to test. I thought it only does this because I'm on my localhost.

[DarkWater]

It's because you're on your localhost.  It should work as expected on a working web server.  But I know that AOL users can change IPs (unwillingly, mind you) on every request sometimes.  Which could be a problem.  I remember a post about it a while ago and someone linked to an article on it after someone was skeptic.

[Prodigal Son]

I see, good to know. But as far as limiting posts for unregistered users this is the best you can do right? Checking IP's is the only thing I can think of or is there another method I could use?