Entire Linux Network stack diagram (2024)

[elevation]

This place needs more of this kind of documentation.

I failed to use IP tables for years. I bought books. I copied recipes from blog posts. Nothing made sense, everything I did was brittle. Until I finally found a schematic showing the flowchart of a packet through the kernel, which gives the exact order that each rule chain is applied, and where some of the sysctl values are enforced. All of a sudden, I could write rules that did exactly what I wanted, or intelligently choose between rules that have equivalent behaviors in isolation but which could have different performance implications.

After studying the schematic, every would just work on the first try. A good schematic makes a world of difference!

[HotGarbage]

Was it this one? https://en.wikipedia.org/wiki/File%3aNetfilter-packet-flow.s...

[PunchyHamster]

It is also worth mentioning TRACE target that will dump to logs which exact rule the packet hit, it's invaluable big firewalls.

[waynesonfire]

> I failed to use IP tables for years.

Me too, then I discovered FreeBSD and pf tables. I _feel_ like an expert network engineer now. It took time and effort of course, but the learning process "clicked" for me all along the way and I was able to build on my understandings. Give it a try!

https://docs.freebsd.org/en/books/handbook/firewalls/

There was a recent book published on the tool, The Book of PF, 4th Edition

[Koffiepoeder]

Can you share the diagram? Would love to become iptables-enlightened.

[hhutw]

For anyone who is interested, the author of this diagram also made a Linux disk I/O diagram (https://zenodo.org/records/15234151). These diagrams are from his book Operativni sustavi i računalne mreže - Linux u primjeni (https://zenodo.org/records/17371946)

Shout out to the brilliant and generous work of the author!

[N-Krause]

Do you know if there is a English version of the book?

[stuxnet79]

The Disk I/O diagram is excellent, thank you for sharing.

[rfmoz]

Linux Kernel map is an other good one https://commons.wikimedia.org/wiki/File:Linux_kernel_map.png

[colordrops]

I'm surprised to realize I'm familiar with most of the stack just from decades of Linux usage and no formal study of the stack.

[rolandog]

Thanks Hrvoje Horvat for such a detailed diagram! It'll help me learn the Network stack much, much easier.

His book "Operativni sustavi i računalne mreže - Linux u primjeni" [0] (Operating systems and computer networks - Linux in use) may well make learning Croatian worth it! Congrats on publishing, and thanks for such an invaluable contribution!

[0]: https://zenodo.org/records/17371946

[jruohonen]

That's pretty cool!

If someone could program a visualization tool that would generate such diagrams automatically, that would be even cooler (but likely a mission impossible).

[alhirzel]

Automatic generation would be really tough because of all the levels of abstraction traversed in this diagram in particular... But tools like Mermaid / PlantUML can get you in the ballpark, and PGF/TikZ could be a reasonable target if you want to attack that mission by generating text instead of images.

[mixedbit]

For containers you will also have own TCP/IP stack similarly to what is shown for VM on the diagram, this is done when a container uses slirp4netns to provide networking. An alternative is to use kernel TCP/IP stack, this is done when pasta is used for networking, diagram on this page shows the details:https://passt.top/passt/about/.

[billfruit]

Is it possible we see the diagram as an svg? I am seeing it only as embedded in the pdf, and really difficult to read .

[makkes]

Click on "Download" below the embedded PDF viewer and you'll get the PDF.

[elcapitan]

Is there some sort of equivalent to this book but in English, which explains and diagrams the Linux network stack? Doesn't need to be all in one, I feel like having a more high level overview and then subsystem diagrams with explanations would work as well.

[roomey]

I'm not sure if this takes into account para-virtualized networks on VMs, ie. VMware vm's with "virtual" hardware access

It's been a few years for me tho, so perhaps it's covered with the VM section.

Lovely diagram, thanks for sharing it!

[SSLy]

These usually attach in the bridge or NAT flow.

[PunchyHamster]

*simplified.

Doesn't even go into iptables/nftables

[ainiriand]

If you look closely to iptables, iptables looks back at you.

[zvmaz]

Incredible work! I really wish the author's book had an English translation.

[dns_snek]

Are machine/AI translations viable for technical books like that [1]? It's CC-BY-SA licensed if anyone wants to give it a go.

[1] https://zenodo.org/records/17371946

[RossBencina]

Any recommendations for a map of Linux user-space network management options?

[phrotoma]

Anyone figure out what the colour scheme means?

[jaeyson]

Good thing we have Hacker News

[alhirzel]

s/Aplication/Application/g

[nolist_policy]

qdisc is too small in this diagram and to easy to miss.

[ee99ee]

wow

[snvzz]

Fools admire complexity.

[9dev]

There’s complication, and there’s complexity. Fools admire complication, engineers design solutions to complex problems. This is a diagram explaining the latter.

[yjftsjthsd-h]

Where/how would you simplify it without losing features?