By Joel Snyder
Network World, 02/11/02
Original Article on Network World Web Site
Many companies are much more dependent on the Internet than they've ever been. With e-mail, Web-based commerce and VPNs becoming a larger part of most businesses, the Internet is no longer optional.
This means you need to start treating the Internet as if it were part of your network and not some foreign land outside the firewall. For best results, focus on three areas: reliability, management and reporting.
Reliability is the same old story: Are you ready for a disaster? Do you have a back-up plan? This has been hashed out so many times in recent weeks that we don't need to go over it again, except to emphasize that you need a plan for those times when your Internet line goes down or your ISP goes belly-up.
Management means knowing how the Internet is behaving today. Your best tools are the old standbys, ping and traceroute, plus NSLOOKUP for DNS maintenance. Get good versions for your own desktop and learn how to use them.
Ping generally is useful only on a LAN because so many administrators block Internet Control Message Protocol echo packets. Traceroute is really the tool of choice. There are lots of good traceroute tools out there and a bunch of lousy tools. Beware of a traceroute that promises things that are impossible, such as geomapping of the Internet. I use Nanog Traceroute, which I believe is the best. You can get a list of good traceroute implementations at http://www.traceroute.org/.
Figure out all those obscure traceroute options, such as Loose Source and Record Route (LSRR), which are vital for viewing paths in both directions. Now that symmetric routing is a thing of the past, you need to know a lot more about the topology of the Internet to solve problems. If your ISP blocks LSRR packets, as some naive ISPs do, find a new ISP that understands how to operate a backbone. You should also find an Internet-located traceroute server, which can give you a third point of view. (Traceroute.org is a good place to start, or you can use the one I run at www.opus1.com/www/traceroute.html.)
Reporting means knowing how well the Internet is behaving. Get a reporting tool and use it to track Internet uptime, latency and throughput. I use the outstanding freeware Multi-Router Traffic Grapher for bandwidth statistics and Ipswitch's WhatsUp for uptime and latency, but there are lots of options if you don't like either of those.
What is our Internet uptime? What do we do if our main link goes down? How much bandwidth are we using? What is the latency to our most important sites? And how do the packets get there and back? If you can answer those five questions, you'll have properly integrated the Internet into your network management.