Firewall

Features

• Packet filtering
• NAT

Explanation

• A Firewall is basically designed to stop unauthorized access from and to protected computer networks. Firewall is usually implemented to stop illegal access or trespassing from the Internet to privately held LANs that have Internet access.

• Arescom routers with the packet filtering feature can act as a firewall for your network. The router with packet filtering enabled will examine each packet leaving or entering the network. The router will accept or reject the packets based on user-defined filtering rules. The packet filtering feature of the router works whether the router's WAN IP (EZRider) or ISDN IP (Apex1100/Netlinker 7x) is assigned dynamically or statically. With a dynamically assigned IP address the private network recieves additional security protection because potential intruders would have to find out the correct IP address to enter the private network first.

• Besides a packet filtering feature, Arescom routers can also protect your LAN by utilizing NAT (Network Address Translation) technology, RFC 1631. NAT basically takes one legal Internet IP and shares that IP with the private LAN. NAT technology hides your internal LAN from the Internet. The Internet is not accessible to your LAN except via the router. All the packets coming in or going out the router are translated through the router. Therefore, internal LAN PCs are hidden from the outside network. This creates another layer of security from potential attack.

• The proxy server or software has a similar function as the router. Proxy servers in general are software solutions, which enable private LANs to get on the Internet. Proxy programs sometime require LAN users to reconfigure their Internet related application for correct use. Routers on the other hand do not require reconfiguration of the program. Proxy servers also utilize packet filtering to stop trespassing packets, but it usually requires more extensive configurations than routers. Routers have no moving parts as compared to a proxy server installed on a dedicated PC which uses a hard disk system, and is more prone to system failure.
  Proxy needs a gateway to send out going bond packets. Routers skip this step since the router itself is the gateway. This will place the performance edge on router in processing TCP/IP commands.