Lect 15B Firewall

Firewall Deployment Topologies 19 Internet Packet filtering router Server Bastion host Private network hosts.
Screened host firewall system – dual-homed

The Office of Medicaid (MassHealth) paid questionable or unallowable medical claims totaling $35,137,347 during our audit period for non-emergency services provided to Limited

application-level gateway bastion host circuit-level gateway distributed firewalls DMZ firewall host-based firewall IP address spoofing IP security (IPsec) packet filtering

If the firewall comprises a bastion host, the packet filtering rules should further restrict traffic flow ( → screened host architecture):. As in the modified rules above only

‰ In a screened subnet firewall, two packet filtering routers are set up: ‰ one for traffic allowed between the Internet and the bastion host, and ‰ one for traffic allowed

•  Stateless packet filters •  Stateful packet filters •  Application gateways •  Circuit-level gateways ❍  Firewall configurations •  Dual-homed •  Screened

„ Bastion host uses a single firewall with two interface cards „ Screened subnet uses a single firewall with three

 The bastion host is protected from external hosts by an outer packet filter  The internal hosts are protected from the bastion host by an inner packet. The Split Screened