| What is the purpose of a Firewall? | | | | replayed. Powerful user authentication makes use of |
| Firewalls are absolutely vital for keeping network | | | | cryptography, for example SSL certificates. A |
| security in force. The firewall stops and controls the | | | | certificate of this sort can prevent "replay attacks" |
| traffic that comes between your network and the | | | | from occurring. A replay attack happens when a user |
| different sites you go to. A firewall is a constituent of a | | | | name and password are captured and used again to |
| company's network protection, and it acts to keep in | | | | gain unauthorized access. |
| force the network security policy. It can log | | | | Firewall-to-firewall encryption |
| inter-network activity with efficiency. It can also reduce | | | | A connection that is encrypted is sometimes called a |
| a network's vulnerability. Whenever an organization is | | | | VPN, or Virtual Private Network. Cryptography makes |
| connected to the Internet but is not using a firewall, any | | | | this more or less private. Of course it isn't really private. |
| host on the network has direct access to all resources | | | | The information may be private but it is sent on a |
| on the internet. If you don't have a firewall, every host | | | | public network -- the Internet. While VPNs were |
| online can attack every host in your network. | | | | available before firewalls were, they became more |
| What is a Firewall Incapable of Doing? | | | | common when they began running on firewalls. Today, |
| Firewalls can't always detect malicious data. For the | | | | most firewall vendors offer a VPN option. |
| most part they cannot offer any protection against an | | | | Additional Purposes of Firewalls |
| attack from inside, although they may log network | | | | - Increasingly, firewalls are being used for purposes of |
| activity should the criminal use the Internet gateway. A | | | | content filtration. Virus scanning is a common addition |
| connection that doesn't go through a firewall cannot be | | | | to firewalls in this area as well. Though this may be a |
| protected by a firewall. To put it another way, if you | | | | waste of resources, because filtering for viruses |
| connect directly to the internet via modem, there is no | | | | needs to be carried out by every computer since |
| way the network firewall can protect you. Some | | | | information might be transmitted to these computers |
| firewalls cannot protect from viruses. Firewalls also | | | | via routes besides through the firewall itself - for |
| cannot totally protect against previously unknown | | | | example, via separate disks. |
| attacks; while a simple firewall provides little protection | | | | - URL Screening: Firewall regulated accessibility to the |
| against computer viruses. | | | | internet as well as content filtering of both files and |
| Firewall User Authentication or Verification | | | | messages appears to be a practical extension of a |
| You establish a claimed identity's validity via user | | | | firewall. The drawback of utilizing a firewall for URL or |
| authentication. The use of a password and user name | | | | content filtering is minimized performance. |
| can provide this authentication; however, it is not really | | | | - To restrict the size of network space that any single |
| strong authentication. When you use a public | | | | user can occupy, or restrict the amount of the |
| connection, for example if you have a connection to | | | | network's bandwidth that may be utilized for given |
| the Internet that is not encrypted, your user name and | | | | purposes. |
| password can easily be copied by other people and | | | | |