Your phone begins ringing before you find a suitable spot to put down your first comforting cup of coffee in the morning. Users are complaining that the network is slow - web browsing sessions are painfully sluggish and email takes forever to download. They state that they simply can't work this way.

The problem appears to be widespread as your coffee cools faster than the users' tempers. A lack of error messages or network alarms makes the problem more elusive and guarantees you'll be hunting down the problem well through lunchtime - at least.

Could the problem be related to the infrastructure devices? Is a rogue switch dropping packets periodically? What about the servers? Could the email server finally be giving in to the pressure of handling all those email chain letters the users pass amongst themselves? What is the chance that the users' systems have been compromised with a virus or bot that is spreading stealthily through the shadows of the network like the plague?

In this white paper, we examine how to use Wireshark, the world's most popular open-source network analyzer, to troubleshoot some of the top causes of poor network performance, including

• High latency
• Packet loss
• Inefficient window sizes
• Intercepting devices
• Application dependencies