FIREWALL

FIREWALL

1. A firewall is inserted between the premises network and the internet

2. access control techniques

   • service control - type of internet service accessed inbound and outbound
   • direction control - direction in which particular services may be initiated
   • user control - access to a service is controlled according to user
   • behaviour control - controls how particular services are used

3. scope of Firewalls

   • single choke point
   • singular monitoring point
   • platform for non security functions
   • platform of IPSec

4. type of firewalls

   • packet filtering router
     • packet filtering attack
       • ip address spoofing - packets from the outside have internal addresses in their source IP address field
       • source routing attacks - route of packets is specified to bypass security measure
       • tiny fragment attack - designed to circumvent filtering rules that depend on TCP header information
   • application level gateway
   • circuit level gateway
   • Hybrid firewalls

5. bastion host

   • bastion host, single-homed
   • bastion host- dual-homed

6. screened subnet

7. DMZ guidelines

   • keep it simple - simple firewall, the more secure and more manageable
   • use devices as they were intended to be used
   • create defense in depth
   • pay attention of internal threats

8. other type of firewalls

   • host-based firewalls
   • personal firewall appliances