Key Concepts
Software Firewall
Hardware Firewall
Disable
FTP Test
Error 10065
What does this tutorial Cover?
What is a firewall?
What are the types of firewalls?
How does a firewall work?
What protection does a firewall offer?
How can a software firewall affect my internet connection?
Test if a firewall is blocking internet access?
What is a firewall?
A firewall is a system designed to prevent unauthorized access to or
from a computer or private network. A firewall can be implemented in both
hardware and software, or a combination of both. They are frequently used to
prevent unauthorized Internet users from accessing computers or private
networks connected to the Internet. All messages entering or leaving the
computer or private network pass through the firewall, which examines each message
and blocks those that do not meet the specified security criteria.
What are the types of firewalls?
Software (or Personal)
Hardware Firewall (physical device)
Software (or Personal)
A software firewall is an application that has been installed on the
computer. The firewall will inspect internet traffic and traffic generated from
the pc intended for the internet.
Popular Vendors:
Norton
ZoneAlarm
McAfee
Black Ice
Hardware Firewall
A hardware firewall is a separate physical device. In general, a
hardware firewall can inspect internet traffic faster and more in-depth than a
software firewall.
Popular Vendors:
Cisco
WatchGuard
Checkpoint
How does a firewall work?
Firewalls use one or more of following three methods to inspect
internet traffic flowing in and out of the PCs internet connection:
Packet Filtering – Internet traffic is compared against a list of
rules. If the traffic matches a rule, then the traffic is allowed. If the traffic
does not match a rule, then the traffic is discarded.
Proxy Service - Information from the Internet is retrieved by the firewall and then sent to the requesting system and vice versa.
Stateful Inspection - A newer method that doesn't examine the contents of each packet but instead compares certain key parts of internet traffic to a database of trusted information.
What protection does a firewall offer?
One of the best things about a firewall from a security standpoint is
that it stops anyone on the outside from logging onto your computer.
A firewall can block the following type of traffic:
Remote login
Application
SMTP session hijacking
Operating system bugs
Denial of Service
E-mail bombs
Macros
Viruses
Spam
Redirect Bombs
Source Routing
HTTP (Ability to view Web Pages!)
HTTPS (Ability to view secure Web Pages!)
How can a software firewall affect my internet connection?
A software firewall can block the following:
Access to secure websites
Internet traffic
Prevent applications from reaching the internet, Ex. Email Client
(Outlook, Outlook Express)
Test if a firewall is blocking internet access?
Access a DOS Prompt
FTP Test
Test if a firewall is blocking internet access? How?
Click on Start, Select Run, Type Command or cmd, Click OK button
At the DOS prompt, type FTP 127.0.0.1 (or FTP “modem’s LAN
Address”) Then hit the ENTER key on the keyboard.
Now, If you receive a socket error 10065, it means that a software
firewall application may be blocking traffic.
But If you receive an Unknown Error Number (Windows XP), this is
normal. If you receive a socket error 10061 then a firewall is not blocking
traffic. Just type "bye" then hit the ENTER key to return
to a normal prompt. Next type Exit and press ENTER key.
Please Remember: Even though disabled, the firewall may still be 'active' in the background.
I hope you enjoyed my tutorial on Firewalls. All feedback is appreciated. Irongeek
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