Abstract

The booming complexity of networks, and the desire to make them more accessible due to the growing
emphasis on and awareness of the Internet as a medium for multi-dimensional transactions, mean that
networks are becoming constantly and increasingly exposed to attacks, internal and external. The research
is on for mechanisms and techniques for the security of internal networks from such attacks. One of the
multiple protective mechanisms under detailed consideration is the firewall. A firewall protects a network
by guarding the points of entry to it. Firewalls are becoming increasingly effective and sophisticated by the
day, and new features are constantly being added, so that, in spite of the criticisms made of them and r&d
trends threatening them, they are still a very strong protective mechanism. This article provides an
overview of firewall using IP tables in Linux.