Intercepting TCP connections and manage firewall remotely

Hello, I am looking on the Internet and manuals, but maybe you can address me quickly on the right feature. I was wondering if it is possible to configure a router Cisco so that it intercepts the events of TCP connection establishment between two hosts (SYN/ACK/SYN-ACK sequence) and notifies a remote server passing to it the information of the IP header (via HTTP, SNMP trap,or others) of the connection. Also, is it possible to programmatically add/remove firewall rules on the fly ? All that I want is to be notified when a connections is established and eventually block it on some cases. Thanks for your help, LB