iRule for specific URL to be sent to singel node in the pool

A few syntactical errors:

1. Your [string tolower ] command should only be encapsulating the HTTP::uri, not the entire string.

   [string tolower [HTTP::uri]]
   

2. Your URL should probably be in double quotes.

3. The [HTTP::uri] command is only going to retrieve the URI portion of the URL, so it would see

   /images/alp/captchaImages
   

4. You don't need to encapsulate the pool name in single quotes.

So assuming you don't really care about the Host portion of the URI, something like this should work for you:

when HTTP_REQUEST {
    if { [string tolower [HTTP::uri]] equals "/images/alp/captchaImages" } {
        pool pool_name member 10.10.10.65 80
    }
}