Bit of Trouble iRule Logic

If the VS didn't have a default pool and a request didn't match any condition which specified a pool, the connection would be dropped. You could handle this by setting a pool in the iRule for all conditions. You can use return to avoid hitting the default pool selection in the iRule:

when CLIENT_ACCEPTED {

    Check client IP against the white list once per TCP connection
   if {[matchclass [IP::client_addr] equals whitelist]}{
      set check_uri 1
   } else {
      set check_uri 0
   }
}
when HTTP_REQUEST {

    Check the URI if the client IP was in the whitelist or if the True-Client-IP header is
   if { $check_uri or ([HTTP::header "True-Client-IP"] ne "" and [matchclass [HTTP::header "True-Client-IP"] equals whitelist)}{

       Check the requested URI
      switch -glob [HTTP::uri] {
         "*1A1*" { pool 1A1; return }
         "*1A2*" { pool 1A2; return }
      }
   }
    If we haven't exited the event already, select a default pool
   pool default_pool
}

Aaron