FireWalls. David Palmi and Scott Bauer. What is a Firewall?. “Firewall” means a fireproof wall. Narrow point of access for traffic entering or leaving a network. Positioned at the entry point to control access. First to see incoming, and last to see outgoing traffic.
David Palmi and Scott Bauer
Fields in red are our focus.
Range for private addresses:
Class A: 10.0.0.0 to 10.255.255.255
Class B: 172.16.0.0 to 172.31.255.255
Class C: 192.168.0.0 to 192.168.255.255
240.0.0.0 to 247.255.255.255
What should your machine do if it receives a packet with a forged address?
Deny or Reject?
Packet Filter must be able to recognize the “start of connection” TCP packets.
A rule list should not allow start of connection from outside the system.
Only allow start of connection from the client side.