How can I simulate TCP/IP errors?

Question

On a multi-tier application, I need to simulate various TCP/IP errors to test some reconnection code. Does anyone know of any tools (Windows based) I can use for this purpose? Thanks.

Answer 1

No tools that I'm aware of, but most of TCP errors can be emulated by a custom LSP filter. This article can get you started writing one

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Answer 2

Try netwox (formerly lcrzoex.) If it won't do it, it can't be done. It contains >200 tools.

Answer 3

Scapy allows you to control every aspect of the packets, and randomly modify ("fuzz") the ones you don't want to control. If you're a command-line kind of guy, it's a great tool.

Answer 4

On FreeBSD, the best tool, by far, is dummynet, "a tool originally designed for testing networking protocols, and since then used for a variety of applications including bandwidth management. It simulates/enforces queue and bandwidth limitations, delays, packet losses, and multipath effects."

On Linux, you will have to use netem. (It seems there is now a port of dummynet but I never tried it.)

More details (in French) in my article.