Traffic accounting through NAT box

[Pedro Ortigão <pmo@xxxxxxxxxx>]

Hi all,

Is there some add on to have simple statistics of the connections that go 
through the NAT box?
What I'd need was someway to have a daily/mothly file with the following info 
per connection:
Source IP (Local); Destination IP; Destination Port; Total Bytes; Connection 
duration


Thanks in advance,
Pedro