Kind of Limits

[bright true]

Hello , 
 i have no experience with iptables at all ... i just want to get my problem 
solved , i hope you can help me
 How can i limit the number of connection or not limiting , let's say 
 when the number of connections reach the ALLOWED numbers of connections it 
will get block for about 2 minutes or something 
 NOTE : i want it to work for all destination ports 
 please reply me with something helpful with out the need of re-compiling 
the Kernel or installing a patches
  Thanks in advance