iRule to redirect to URLs

You should use a more optimized solution with "switch" instead of "if"

https://devcentral.f5.com/articles/irules-optimization-101-01-if-elseif-and-switch

Code
   when CLIENT_ACCEPTED { 
    switch -glob [IP::client_addr] { 
        "192.168.5.*" { pool pool1 } 
        "192.168.6.*" { pool pool2 } 
        "192.168.7.*" { pool pool3 } 
        default { pool default_pool }
    }  
  }