You can use dummynet ofcourse, There is extension of dummynet called KauNet. which can provide even more precise control of network conditions. It can drop/delay/re-order specific packets (that way you can perform more in-depth analysis of dropping key packets like TCP handshake to see how your web pages digest it). It also works in time domain. Usually most the emulators are tuned to work in data domain. In time domain you can specify from what time to what time you can alter the network conditions.

虚拟网

试试这个基于FreeBSD的VMWare映像。它还有一个很好的操作指南，完全免费，20分钟就能站起来。

更新:DummyNet现在也支持Linux, OSX和Windows

尝试交通整形XP 你可以用这个应用程序轻松限制IE或其他浏览器的速度，它也是免费的

我已经成功地使用TMnetSim(页面底部，在“其他工具”下-链接显示类似于“ZIP: TMnetSim网络模拟器2.4 32位(600KB)”

它不仅仅适用于网站——你可以减慢任何TCP端口的连接。我用它来模拟一个缓慢的SQL Server(端口1433)。

对于Linux和OSX系统，可以使用ipfw。

来自Quora (http://www.quora.com/What-is-the-best-tool-to-simulate-a-slow-internet-connection-on-a-Mac)

本质上是使用防火墙来限制所有网络数据:

定义一个规则，该规则使用管道重新路由来自任何源的所有流量 地址到任何目标地址，执行以下命令(作为 Root或使用sudo): $ ipfw添加管道1从任意到任意 配置此规则，将带宽限制为300Kbit/s，并强制 每次200ms的延迟: $ ipfw pipe 1配置bw 300Kbit/s delay 200ms 删除所有规则并恢复原来的网络连接: $ ipfw flush

如果你在为Windows Phone开发时需要模拟网络连接质量，你可以尝试一下Visual Studio内置的名为模拟仪表板的工具(更多详细信息请访问http://msdn.microsoft.com/en-us/library/windowsphone/develop/jj206952(v=vs.105).aspx):)

You can use the Simulation Dashboard in Visual Studio to test your app for these connection problems, and to help prevent users from encountering scenarios like the following: High-resolution music or videos stutter or freeze while streaming, or take a long time to download over a low-bandwidth connection. Calls to a web service fail with a timeout. The app crashes when no network is available. Data transfer does not resume when the network connection is lost and then restored. The user’s battery is drained by a streaming app that uses the network inefficiently. Mapping the user’s route is interrupted in a navigation app. ... In Visual Studio, on the Tools menu, open Simulation Dashboard. Find the network simulation section of the dashboard and check the Enable Network Simulation check box.