For most businesses, Internet access is as important as telephone and fax services. And when small businesses compete against larger enterprises, the pressure is on to perform. Failing to promptly reply to an important client because your Internet connection is down doesn't cut it. Reliable Internet access is even more crucial when you run your own email server, provide remote access to remote users, or host other servers that must be accessible to the outside world. Unfortunately, the business broadband Internet services that small businesses can afford often resemble consumer services, with a higher price tag but with somewhat unreliable service and unpredictable speed.
If you work for a small-to-midsized business (SMB), you might think keeping up with your larger competitors is impossible. But advances in hardware and software, plummeting prices, and the Internet let you leverage technology opportunities to compete without losing the responsiveness that comes with being smaller. The trick is that you must be aware of available services and innovations and do some out-of-the-box thinking. By using dual-WAN routers, you can get highly reliable Internet access for dollars a month—and even connect multiple locations in one WAN.
Dual-WAN Routers
Thanks to the deregulation of the telecommunications market, most companies have several choices of Internet providers and at least two technologies—cable and DSL. Suppose you could subscribe to both cable and DSL, connect them to a small box, then connect the box to your LAN? What if the box functioned like a consumer Internet gateway—but with a few added features? This box would let you use both Internet connections for higher bandwidth when both services were functional; however, if either Internet service failed, the box would transparently route traffic over the remaining connection. This scenario might sound too good to be true, but it isn't.
Several vendors offer dual-WAN routers that provide this type of fault-tolerant Internet access, and the best part is the price: $250 to $500 per router. Figure 1 shows a dual-WAN router and two ISP connections connecting an internal LAN to the Internet. Although the figure shows the use of two-way satellite technology, if two land-based Internet providers are available, I recommend that you use them. They'll provide greater speed and reliability.
My firm is an SMB that competes with much larger firms for audits and related security services, and I could go without telephone service more easily than without my Internet connection. Over the years, I've tried both cable and DSL; both work most of the time. Before I tried a dual-WAN router, I had decided to subscribe to both cable and DSL. However, that meant manually switching between the two services, and one service is basically wasted when both are functioning. I've now used a dual-WAN router for about a year. After a few initial bumps in the road, this solution has provided smooth sailing.
I contacted several companies, explaining that I wanted to test their dual-WAN routers for this article. XiNCOM sent both its XC-DPG502 and XCDPG603 routers. I used the XC-DPG502 because it was less expensive and had the basic features to provide highly reliable Internet access. Although I discuss the dual-WAN solution from the standpoint of the XiNCOM router, the setup and considerations apply to other vendor offerings, including routers in the XiNCOM DPG500 and DPG600 series, the Symantec Gateway Security 300 Series, Linksys RV082, and the HotBrick VPN 800/2.
Setting Up a Dual-WAN Router
The first step after choosing a router is to configure its LAN port and one of its WAN ports with the appropriate IP settings. When you first bring up the XC-DPG502, it (like most gateways) defaults to being a DHCP server and leases out addresses from the 192.168.1.0 subnet. Your dual-WAN router will replace your current firewall/router and take the place of your current default gateway in the IP configuration of systems on your network.
Configure the router. Before you connect your dual router to your internal network, log on to your current gateway and record the configuration for both its Internet connection and the internal network. You'll need to know the username and password that the gateway uses to connect to your ISP and whether the Internet address is static or provided dynamically by the ISP through DHCP. If you have a static IP address, record the subnet mask, default gateway, and DNS server addresses so that you can easily get connectivity going on one port of your new dual gateway. For the internal-network configuration, record the gateway's local network address and subnet mask. If your gateway is also your DHCP server, note the range of addresses from which the server currently leases.
Also before you connect the dual gateway to the network, connect a PC to an internal LAN port on the gateway. (The XC-DPG502 and most other models have four internal ports.) After your PC gets an address from the gateway, open a browser and log on to the gateway with that address. Configure one of the gateway's two WAN connections with the parameters of your current gateway's Internet connection. Figure 2 shows the configuration of both ISP connections on my XCDPG502. (The IP addresses have been changed to local 10.*.*.* range addresses, but in the real world the addresses would correspond to the actual public Internet addresses that your ISP assigns.) Configure the internal LAN interface of the new router with the same IP address as the old router. Figure 3 shows the internal LAN configuration.
This approach lets clients continue to access the Internet without changing their default gateway. If your old router provided DHCP services, configure the dual router to be a DHCP server. (Doing so gives you access to other devices on your network even if your Windows server goes down.) However, you might consider leasing from a different range of addresses so that the new router doesn't inadvertently lease out addresses that other clients already use. As current leases run out, computers will automatically obtain a new address from the new range. Just make sure your DHCP range and the internal address of the router don't conflict with any servers or other devices on your network that have static addresses (e.g., printers, wireless access points—APs).
If some other device or server on your network serves as your DHCP server, you might need to adjust the options that the DHCP server configures for new clients. As long as the old and new routers share the same internal LAN IP address, you don't need to change the default gateway that the DHCP server assigned. Regarding DNS server addresses, your DHCP server probably assigned the router's internal address as the DNS server. If so, no change is required to your DHCP server. Or, if you run your own DNS server on your internal network, your DHCP server might have specified the address of a local DNS server. (If you have an Active Directory—AD—domain, you run your own DNS server.) A third possibility is that your DNS server configures clients to use DNS servers on the Internet (usually your ISP's DNS server). In this case, you need to change the setup because you now have two ISPs. If one ISP connection goes down, your clients won't have access to Web sites because they won't be able to resolve domain names to IP addresses. To solve this problem, configure your DHCP server to instruct clients to use the router as their DNS server. The router then forwards DNS requests to either ISP's DNS server.
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