Firewall

A firewall is implemented to protect unauthorized access to or from a private network. It can be implemented in both software and hardware or a combination of both. Firewalls are regularly utilized to protect unauthorized internet users from accessing private networks connected to the Internet. All data sending or receiving the intranet passes through the firewall, which can inspect each information those does not meet the particular security criteria.

Common firewall techniques

Commonly, firewalls are utilized to prevent both corporate and home networks. A distinctive firewall application sorts out all data coming through the Internet to your network or PC. There are various kinds of firewall techniques that will protect infected data from getting through:

• Packet Filter:  This technique is designed to examine at each packet of data entering or leaving the network and allows or rejects it depending on user-defined set of rules. It is quite effective and transparent to users, but this is hard to configure. Moreover, it is vulnerable to IP spoofing.
• Application Gateway: This technique applies to FTP and Telenetservers to enhance security mechanism. This is very efficient, but can inflict a performance deprivation.
• Circuit-level Gateway: This applies security mechanism when a Transmission control Protocol or User defined Protocol connection is created. Once the connection has been established, data packets can flow between the hosts without further examining.
• Proxy Server: Intercepts all information entering and leaving the network. The proxy server successfully hides the true network address.

Advantages:

• Cost is inexpensive
• Secure your system from intruders
• Can even protect multiple systems simultaneously

Disadvantages:

• It takes more time to get its traffic onto a particular network
• Can degrade your system’s performance
• Some firewalls do not find viruses, worms, Trojan etc