Dynamic packet filtering filters packets based on:
1) Administrator defined rules governing allowed ports
and IP addresses at the network and transport layers of
the OSI network model.
2) Connection state which considers prior packets that
have gone through the firewall.
3) Packet contents including the application layer
contents
Static packet filtering only filters packets based on
administrator defined rules governing allowed ports and
IP addresses at the network and transport layers of the
OSI network model as mentioned in item 1 above.
Therefore dynamic packet filtering also called state-full
inspection which provides additional capabilities including
inspection of packet contents up to the application
layer and consideration of the state of any connections.
Dynamic packet filtering provides a better level of security
than static packet filtering since it takes a closer
look at the contents of the packet and also considers previous
connection states.