IP Routers : Speed, Security and Economy

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Chances are you need (at least) one! Unless somebody printed this up and handed it to you, you are probably connected to the internet right now, and without overstressing the point, your computer and sensitive personal data are subject to attack.

Software "firewalls" are available to prevent intrusions, but they operate on data that has already reached your computer, and they are in no way as robust a defense as an NAT router. These programs usually come with a one-year license, while a good router will last almost indefinitely and may even cost less.

Firewall software is actually much better at stopping outgoing malware than preventing incoming attacks. While this is important, it's not what most home & small business users need.

As you probably know, TCP/IP is the protocol suite computers use to "talk" to the ineternet -- IP stands for "Internet Protocol". When you set up internet connections, you are generally asked for several IP addresses.

These addresses consist of four eight-bit "octets" separated by dots. If your binary math is up to speed, you know that 2 to the eighth power is 256, so these octets have values from 0-255.

If you picture the network as a tree, the leftmost octet would represent the trunk, then as you move to the right you would traverse limbs, branches, twigs, and finally end up at a leaf, which would be the address for a particular network device -- a certain number in the final octet.

The first part of the IP address represents a network, and the second part is a subnet -- which is where the mysterious "netmask" comes in. A valid netmask is a series of ones followed by a series of zeroes The ones indicate which digits are part of the network address, and the zeroes indicate the number of places occupied by the subnet.

Since networks and subnets are commonly divided at octet boundaries, netmasks are generally one or more "255s" followed by "0s". Other netmasks are possible, but we won't go into that here.

When you set up network connections -- including your internet connection -- you can assign a static IP address to a node (or "leaf" in our tree analogy) or you can use DHCP.

If you had nothing to go on but Microsoft documentation, there's no way you'd opt for DHCP, but it's actually very simple. You just select DHCP client in the TCP/IP configuration of your computer or other device and enter the address of the DHCP server -- in this case, your router.

When you boot your computer, it will send a signal out over the network asking the DHCP server to assign it an IP address. The DHCP server sends one back, and the IP address is set to that value.

Although this is a little more complicated than static IP addressing, it has several advantages. The main one we will be considering is that DHCP addressing is usually necessary in order to enable Network Address Translation (NAT).

In order for the Internet to work, every point on the net needs a unique IP address. For instance, this page is located at 209.81.84.27/IP-Routers/ although you probably used the more user-friendly DNS name www.squidoo.com/IP-Routers/

Domain registration services assign IP addresses to registrants so no two people pick the same IP addess. There are however, some "private subnets" -- blocks of IP addresses that are never assigned -- that people can use on their local intranets.

These address blocks are treated differently throughout the internet, so a request for the private subnet address "192.168.x.x" for example, wouldn't get far. In Network Address Translation, your router converts public addresses (like the one your ISP assigns to your modem) to available private subnet addresses. Therefore a hacker trying to reach your computer at 192.168.69.70 wouldn't get to first base.

No computer is ever 100% safe from a skilled and determined hacker, but an NAT router -- or better yet, an "external" router configured to address a second "internal" router -- will certainly frustrate all but the most determined attacks.

Given that high-quality routers are cheap and easily available, it is extremely desirable that anyone who values their data get should have at least one on their internet connection.

Although the preceding information may seem a little complicated, most routers come with installation software and/or documentation that will easily "walk you through" the setup process.