I know a lot about how to set up and maintain firewalls, i know their features etc but do not know a lot about how exactly they work.

 

there are two types of firewall: Hardware and Software firewalls.

 

Hardware: these are basic firewalls which block out any unrequested packets.

 

Software: a software firewall is what is essential for ALL computers connected to the internet (that is assuming you do not wish to be hacked), software firewalls do the same job as a hardware firewall + more.

 

It is this "+ more" which means that a hardware firewall (often found in servers/routers) are not really adequate for your main firewall... i tend to think of it this way:

'hardware firewalls block out 99% of amateur hackers, software firewalls block out 99% of professional hackers.'

whilst the figures are inaccurate and made up, it gives people the general idea.

 

now i know that above lot as a fact, however i am interested in this "+ more", what exactly is it and how does it work?

 

(that may seem a strange question seeing as i just told you about it, its just like seeing a battery, knowing it makes a current just not knowing how it makes the current... i know about the software firewall's "+ more" and i know it blocks out hackers almost entirely, i just dont know how)

 

finally on firewalls i think i'll add here that it is a very wise step to 'stealth all ports' this is an option available on most firewalls (software only... hardware cannot do this) and is a very useful thing... accessing your ports is how many hackers work, if you stealth your ports and have a firewall running it is hard for someone to hack you as they cannot get in through your ports and your firewall would catch a trojan or backdoor sending out it's signal.

also: if u have an old pc like PIII 300MHz then you can turn it into a firewall by installing a firewall OS. can't remember the names. i think IPcop was one of them