Can I use pfsense or m0n0wall to simulate WAN-like packet loss, jitter, duplication, and reordering?

I see questions looking for dedicated solutions like: What tool(s) can I use to simulate a WAN for HTTP traffic?

But, I'd like to know if it can be done with a regular router distro too. Ideally as a transparent Ethernet bridge, not an actual router.

Thank you

2 Answers 2


It seems that both PFSense and m0n0wall support dummynet traffic shaper.

dummynet is 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.

  • Thank you. Do you happen to know how to configure PfSense/m0n0wall to simply bridge two nic cards at the Ethernet level with a dummynet filter in between?
    – nonot1
    Commented Jun 10, 2011 at 15:50
  • Don't know about PFSense/m0n0wall, but, as they being based on FreeBSD, you could try reading FreeBSD Handbook about bridge and ipfw.
    – AlexD
    Commented Jun 10, 2011 at 16:36

The best way to do this is probably by using the netem kernel module. See here for more detail. It will allow you to do any and all of the above and then some. This has been part of the linux kernel since 2.6, so should be available in just about any distro by now.

  • Both pfsense and m0n0wall are BSD based - No Linux kernel modules...
    – Goyuix
    Commented Jun 7, 2011 at 15:40
  • Fair call, in which case the answer probably should have been: No, but you can use any Linux distro or IPCop (which is based on Linux). However, I would not recommend using a specialized distro for the purposes mentioned by the OP in any case.
    – wolfgangsz
    Commented Jun 7, 2011 at 15:56

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