Contents

Introduction: What is Firewall?

What Can Firewalls Do?

Types Of Firewalls

Differences between firewall and anti-virus scanner

Ways to Use Firewalls

Ping-O-Matic

Ping-O-Matic

What is Ping-O-Matic?

Ping-O-Matic is a service to update different search engines that your blog has updated.

Why use Ping-O-Matic?

There are usually "spiders" or also know n as Search Indexing Robot that are constantly "crawling" in the search engines.
By updating the different search engines, you'll be able to drive more traffic into your blogs.
This is especially important to business blogs as well as blogs with ads.

 

To Ping-O-Matic

Ping-o-matic

Ways to use Firewall

Differences between a Firewall and Anti-virus Scanner

Types of Firewalls

In the previous post, it's about what is firewall and a brief summary of the development of firewalls from the first generation to the third generation. In this post, it will about the types of firewalls and how they work to provide network security to users.

What Can Firewalls Do?

Many times people tend to fail to realise that there are certain tasks that a firewall can do and there are some that firewall can't do. In this post, you'll be able to have a better idea on what tasks that a firewall can do.

 

Tasks that A Firewall Can Do

A firewall should be able to perform the following tasks:
1. Manages and controls network traffic
2. Authenticates access
3. Act as intermediary
4. Protects resources
5. Records and reports on events

 

Manage and Control Network Traffic

This is one of the main functions that all firewalls should be able to perform. Firewalls manage and control the network traffic by packet inspection and monitoring the connections that are being made which is then filtered.

 

Authenticate Access

This can be done in a few ways. The most common one is by extended authentication or xauth. This is implemented by prompting the user for user name and password prior to the firewall allowing a connection to be established.

Another method would be through the use of certificates and public keys.  This method has an advantage over the use of xauth. There is no need for the user intervention if the hosts are well configured with certificates and the use of well configured public key infrastructure for firewalls and hosts.

Lastly, access can also be verified through the use of pre-shared keys(PSKs) which are less complex to implement as compared with certificates and do not require user intervention. With PSKs, the host is provided a predetermined key that is used for the authentication process.

 

Acts as an intermediary

A firewall can also be configured to act as proxy. A proxy functions by mimicking the host that it is trying to protect. All communications destined for the protected host occurs at the proxy. The proxy will "rebuild" a brand new packet to be forwarded to the protected host. Therefore, there will never be a direct way of communicating with the protected host.

 

Protects Resources

A firewall protects resources from threats by application proxies, stateful packet inspection, use of access control rules or a combination of all.

 

Records and Reports on Events

All firewalls should be able to carry out this task of recording all transmissions so that the administrator will be able to review the recorded data.

Most firewalls use two methods that is syslog or proprietary logging format. These methods enable the administrator to determine what may have occur during a security event. The data logged can also be use when troubleshooting a firewall to help determine the cause of the problems.


Reference:

Wes Noonan,Ido Dubrawsky,Firewall Fundamentals: An Introduction to Network and Computer Firewall Security,Indiana,Cisco Press,2006.

Introduction: What is firewall?

Many times we heard the word firewall and we know that it's something  related to our computer's security but we don't really understand what exactly is firewall. In this post, you'll be able to have a clearer idea of what are firewalls and a little about the development of firewalls over time.

Definition of Firewall

Firewalls are security software or hardware that control access to a network. They can be a combination of both software and hardware too. Firewalls protect all systems against external threats.

They are designed to permit or deny network transmissions based on a set of rules called protocols.

This technology emerged in the late 1980s when the Internet technology is still quite a new technology.

Development of firewalls

First Generation

The first generation is known as packet filtering. The packet filters works by inspecting the packets that are transferred between computers and the Internet. The packet match the packet filters' set of rules then the filter will determine whether to drop or reject the packet that is transmitted.

Second Generation

The second generation is known as stateful filters. It is also known as circuit level firewall. This stateful packet filters can work up to four layers. They work by maintaining  records of all connections passing through the firewalls. These filters can also determine if a packet is the start of a new connection, part of an existing connection or an invalid connection. Another special feature is that these filters can store all packets and search for malicious codes when the packets are combined.

Third Generation

The third generation is known as application layer. Third generation firewalls control inputs, outputs and/or access to,from or by an application  or service. These firewalls can detect if an unwanted protocol is sneaking through non-standard protocol or if the protocol is abused in any harmful ways.


References:
Timothy J. O'Leary, Linda I. O'Leary,Computing Essentials 2012,McGraw Hill,2011
en.wikipedia.org/wiki/Application_layer
en.wikipedia.org/wiki/Firewall_(computing)