INTERNETWORK SCREENS - FIREWALL

Is it worth installing a firewall? It must be done for the same reason you install a lock on your entrance door, in spite of the fact that no lock can guarantee you complete protection. By leaving your network without a firewall, you are just leaving your "door open". So please, "think by yourselves and decide by yourselves...".

Author

Internet is a combination, in the whole planet scale, of a group of networks, which uses a single data transmission protocol - TCP/IP (Transmission Control Protocol/Internet Protocol). A large number of organisations and private users are now connecting to the Internet in order to use its advantages and resources. Businessmen and public organisations use the Internet for many diverse purposes - including electronic mail exchange, distribution of information among interested people and to conduct research. At the present time many organisations attach the existing local area networks to the Internet so that workstations of these local area networks can get direct access to the Internet services.

Connecting to the Internet can have tremendous advantages, though in this case it is necessary to take a serious account of matters concerning the security of the connection... more...



Preface

What is a "firewall" or an internetwork screen?

Rule set-up

Circuit-level gateways

Communication confirmation control

Pipe proxies

PROXY-servers

Bypassing manoeuvres

Application level gateways

Application proxies

Application level filtration

Other protective functions

Stateful inspection firewalls

Best performance, best protection?

Conclusions