How many times have you had a client/server application that works fine when both client and server are in a LAN environment and is painful to use or even unusable when client and server communicate over a WAN? In a typical development environment it’s difficult to test an application over a WAN let alone a number of different WANs with different performance characteristics.
Figure 1 – Typical test network
If you are watching a salesman demo a product using a couple of PCs it’s almost impossible. One solution is costly WAN simulators. If you search the internet you will find many products on the market ranging from very expensive to almost affordable. If your search harder you will find Dummynet which has the advantage of being free.
Dummynet runs under the FreeBSD operating system. It can be booted directly from a CD so you don’t need a special PC. You don’t even need a PC with two Ethernet adapters since you can configure a single Ethernet adapter to have two IP addresses. A laptop and a 4-port switch can convert any development environment or demonstration into a cross continent or ocean WAN. The rest of this article explains how to get, configure and use Dummynet.
WongCupu 