How can I simulate TCP/IP errors?

On a multi-tier application, I n开发者_如何学运维eed 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.

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.

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

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.

Clumsy is a good tool for TCP error simulation on Windows. It can simulate (copy-pasted from link above):

• Lag, hold the packets for a short period of time to emulate network lagging.
• Drop, randomly discard packets.
• Throttle, block traffic for a given time frame, then send them in a single batch.
• Duplicate, send cloned packets right after to the original one.
• Out of order, re-arrange the order of packets.
• Tamper, nudge bits of packet's content.

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