Proxy gateways have a richer set of choices for security policy. Firewall architectures can operate at the application layer, transport layer or network layer of the OSI model. If one inside host connects to an outside address by a modem, the entire inside net is vulnerable through the modem and its host. Firewalls are the most visible part of an installation to the outside and they are the most attractive target for attack Firewalls are targets for penetrators. Firewalls should be kept small and simple, running only the required software so that if a penetrator does get through, the firewall does not have further tools such as compilers, linkers or loaders to continue the attack.
Firewalls are very important tools in protecting an environment connected to a network.
Firewalls can protect against common attacks, such as denial of service, security breaches or configuration changes. They can provide alerts via e-mail, pager, or network management alarms. Firewalls also provide extensive logging and audit trails. All rights reserved.