best method to block ip block

Hi, I want to block all kinds of protocol requests coming from an isp's dialup users since I had enough Superscan pings, icmp +++ath0 attacks the nmap other sorts of tools to scan my ip and also not to forget to mention the back office and other trojan client to server, server to client traffic hitting my firewall. Although these requests are denied at the firewall is there a better way of stopping this. The ip block I want to filter is as follows xxx.156.130.1 to xxx.156.191.255 -- Togan Muftuoglu