DUMMYNET(4)

📦 version 15.1, in freebsd 14.5, freebsd 15.1, nixpkgs unstable

💅 dummynet(4) — traffic-shaping bestie 💅

🌸 NAME 🌸

  • dummynet — traffic shaper, bandwidth manager and delay emulator ✨

✨ DESCRIPTION ✨

Okay so bestie, the dummynet system facility is literally how you control traffic going through the various network interfaces. It applies bandwidth and queue size limitations, implements different scheduling and queue management policies, and emulates delays and losses. It's giving network traffic makeover, no cap. 💖

The user interface for dummynet is implemented by the dnctl(8) utility, so please refer to the dnctl(8) manpage for a complete description of the dummynet capabilities and how to use it. iykyk 🫶

🧵 Kernel Options 🧵

These kernel configuration file options are the ones related to dummynet operation:

  • IPFIREWALL — turns on ipfirewall (needed if dummynet is to be used with ipfw)
  • IPFIREWALL_VERBOSE — turns on firewall output
  • IPFIREWALL_VERBOSE_LIMIT — limits firewall output
  • DUMMYNET — enables dummynet operation
  • HZ — sets the timer granularity

Generally, the following options are required:

options IPFIREWALL
options DUMMYNET
options HZ=1000         # strongly recommended

Additionally, one may want to increase the number of mbuf clusters (used to store network packets) according to the sum of the bandwidth-delay products and queue sizes of all configured pipes. 🌈

🌟 SEE ALSO 🌟

🦋 HISTORY 🦋

The dummynet facility was initially implemented as a testing tool for TCP congestion control by Luigi Rizzo <luigi@iet.unipi.it>, as described on ACM Computer Communication Review, Jan.97 issue. Later it has been modified to work at the IP and bridging levels, integrated with the ipfw(4) packet filter, and extended to support multiple queueing and scheduling policies. 💜

That's the whole DUMMYNET(4) manual page, bestie — from Debian, dated September 10, 2021. Slay! 💅✨🎀

📦 where this page comes from