Types of firewalls
There are different implementations of firewalls that can be arranged in different ways. The various firewall implementations are discussed next and example policies are presented. Table below depicts several firewall architectures and their ratings, as they would apply to low, medium-risk, and high-risk processing environments.
Firewall Security Risk
| Firewall Architecture (If any one of these is being implemented) | High Risk Environment (Hospital) | Medium Risk Environment (Hospital) | Low Risk Environment (Hospital) |
|---|---|---|---|
| Packet filtering Application Gateways Hybrid Gateways | 0 3 4 | 1 4 3 | 4 2 2 |
Note: The rating numbers for various firewall types are as follows: 4, recommended choice; 3, effective option; 2, acceptable; 1, minimal security; 0, unacceptable.
Caution: Actually, universities are very often the targets of attacks and should be considered high risk. They have extremely large conduits to the Internet that, if accessed, can be very desirable and advantageous to pirates for the purpose of launching effective, large scale attacks against industrial/commercial locations such as banks and e-commerce operations.
- Packet filtering
- Application gateways
- Hybrid gateways1
In this tutorial:
- Firewall Security Policy
- Firewall protection
- Firewall architectures
- Multi-homed host
- Screened host
- Screened subnet
- Types of firewalls
- Packet-filtering gateways
- Application gateways
- Hybrid or complex gateways
- Routing versus forwarding
- IP spoofing
- DNS and mail resolution
- Intranet
- Network trust relationships
- Virtual private networks
- Qualification of the firewall administrator
- Remote firewall administration
- Firewall backup
- System integrity
- Physical firewall security
- Firewall incident handling
- Upgrading the firewall
- Revision/update of firewall policy
- Examples of service-specific policies