How can I reduce the number of broadcasts on my network?

improve my network performance. I have 12 servers and about 65 workstations on my network. Network broadcasts are every Administrator's nightmare as they flood the network with, in most cases, unnecessary traffic, consuming valuable bandwidth and in some cases, causing bottlenecks in highly utilized links.

Sources of these broadcasts are network equipment such as routers, switches, network printers, workstations, servers and many more. While having a 'broadcast-free' network is impossible, there are certain steps one can take to ensure broadcasts are minimized.

Before we dive into the action you can take, it is very important you understand the nature and type of network broadcasts running inside your network, and for this, I'd advise you to visit www.Firewall.cx and visit the networking section which contains all the information you will require.

Coming back to dealing with those nasty broadcasts, there are a few steps you can follow that will certainly eliminate a large portion of them:

1. Network Router & Switches

Ensure all network equipment are correctly configured (IP address, gateway, subnet masks, etc.) If you are using any routing protocols or other propriety, i.e. Cisco's CDP, these must be double checked as they are frequently responsible for broadcasts.

2. Network Servers

Again, check your network settings to ensure they are correct according to your setup. Look for any services which are not required and might be causing network broadcasts. Uninstall any unnecessary software which could be contributing to the problem. Scan your servers to ensure they are virus free (very important) and I'd also suggest you download TCP VIEW, which you can do here. This marvelous and incredibly small application will show you all network connections on the machine it is run on, along with the ability to kill and process you require.

3. When you can see … Sniff!

A network sniffer is essential in any type of network. Run your sniffer and watch the incoming broadcasts, trying to identify where they are coming from and what could be causing them. Once you identify the source, focus your efforts on resolving the problem there. If you're lucky, you might even catch other type of traffic you might have been unaware of! In any case, study the results and take action.

4. Breaking the network

In most cases, having up to 50-70 workstations in the same network will not be a problem. But depending on your traffic and the way the network is utilized, it might be a good idea to start looking at segmenting it to help reduce broadcasts, multicasts and increase your local security.

Today's methods of segmentation are fast and more reliable than ever, and involve the installation of VLAN capable switches which can physically and logically segment your network while also providing routing (InterVLAN routing) services. VLANs are a very hot topic and worth looking at. You can find an in-depth analysis of 13 pages and more than 50 diagrams on the topic at www.Firewall.cx.

5. Workstations

Check the node-type your workstations have been configured. This setting dictates how the workstation will request and respond when looking for a master browser or sending a query to it, and can help ease your broadcast traffic quite a bit. Visit Microsoft's support page and search for knowledgebase 160177 – it explains exactly what the node type represents, how it works and what changes must be done in order to select your choice.

I hope that the above will provide you with enough ammo to deal with your problem. On a personal note to all our readers, remember it's more important to understand why something is happening and deal with it, rather than simply taking a few actions hoping it will resolve itself. Take the time and learn how these technologies work...it will pay off in the end!