firehol-dscp(5)

📦
version 3.1.8 · 4 versions
, in debian trixie, ubuntu resolute, ubuntu stonking

💖 firehol-dscp 💖

okay bestie, welcome to firehol-dscp, the FireHOL helper that sets the DSCP field in the packet header. this is from the FireHOL Reference (version 3.1.8), and it's lowkey one of the most useful lil commands for QoS shaping. let's get into it 💅

✨ SYNOPSIS ✨

dscp { value | class classid } chain rule-params

🌸 DESCRIPTION 🌸

so, the dscp helper command sets the DSCP field in the header of packets traffic, which lets you do QoS shaping. it's giving traffic control, it's giving main character energy ✨

Note there is also a dscp parameter which allows matching DSCP values within individual rules (see firehol-params(5)). yes, two different things, same name. iykyk 😭

set value to a decimal or hexadecimal (0xnn) number to set an explicit DSCP value, or use class classid to use an iptables(8) DiffServ class, like EF, BE, CSxx or AFxx (see iptables -j DSCP --help for more information). pick your fighter 💖

the chain will be used to find traffic to mark. it can be any of the iptables(8) built in chains belonging to the mangle table. the chain names are: INPUT, FORWARD, OUTPUT, PREROUTING and POSTROUTING. and bestie, the names are case-sensitive, so don't be out here typing input and wondering why nothing happened 🙈

the rule-params define a set of rule parameters to match the traffic that is to be marked within the chosen chain. see firehol-params(5) for more details 🦋

any dscp commands will affect <strong>all</strong> traffic matched. they <strong>must</strong> be declared before the first router or interface. no cap, put them at the top or they will simply not slay 💀

🌈 EXAMPLES 🌈

# set DSCP field to 32, packets sent by the local machine
dscp 32 OUTPUT

# set DSCP field to 32 (hex 20), packets routed by the local machine
dscp 0x20 FORWARD

# set DSCP to DiffServ class EF, packets routed by the local machine
#              and destined for port TCP/25 of 198.51.100.1
dscp class EF FORWARD proto tcp dport 25 dst 198.51.100.1

🎀 SEE ALSO 🎀

  • firehol(1) — FireHOL program
  • firehol.conf(5) — FireHOL configuration
  • firehol-params(5) — optional rule parameters
  • iptables(8) — administration tool for IPv4 firewalls
  • ip6tables(8) — administration tool for IPv6 firewalls
  • ip(8) — show / manipulate routing, devices, policy routing and tunnels
  • FireHOL Website
  • FireHOL Online PDF Manual
  • FireHOL Online Documentation
  • Linux Advanced Routing & Traffic Control HOWTO

👑 AUTHORS 👑

FireHOL Team. iconic of them, honestly 🫶

and that's the whole vibe, bestie 💜 this page came from the FireHOL Reference, version 3.1.8, built 13 Apr 2025 — go forth and mark your packets, you absolute legend 🌟

📦 where this page comes from