most efficient cloaking

Why use IP and UA?

[mdharrold]

I have read many of the Cloaking posts and just wanted to know why everyone seems to be using IP and UA cloaking for spiders?
Isn't the IP alone be enough to determine who is visiting?

[msgraph]

Basically it is good to have a fail safe method and that is why many use both. Although it does not happen very often, some SE's add new IP's to their pool of robots a few times here and there. If you just base your cloaking on IP address alone then you may get caught with your pants down. :o

Like the other day...

[webmasterworld.com...]

[littleman]

Sometimes humans use the same IPs as the search engine's bots, and sometimes a bot comes in from a unknown IP.

[mdharrold]

Thank you for the lesson. Protecting against any possible occurrence is my biggest problem.

[volatilegx]

If you add UA to your IP detection, be careful of competitors spoofing their UA and sneaking in to your optimized page.

I recommend using only IP but logging events of known search engine UAs with unknown IPs so they can be verified later.