[mtlynch]

I found this a bit too abstract to follow.

It would be helpful if the article explained a practical scenario where you'd want to use this technique.

The only explanation is "Packet redirection is taking a packet from one network interface and injecting it into another," but then there's no attempt to explain why you'd want to do this in practice.

The article also uses a lot of notation without explaining it. It explains what a "veth" is, but it doesn't explain what "veth1@2" or "veth2@1" means. Similarly, it never explains what "netns_1" or "netns_2" are. Are these widely-understood semantics?

[ldelossa]

Thanks for the constructive feedback.

The reason laid out in the article was for "jumping over the default linux network stack" to move a packet closer to its destination. I provide that just to hopefully help, ill have to read thru the article again to see how I can improve on making that clearer or defining more practical wording :).

And yeah, I understand your comments on all the naming spaghetti. I throw together these things so often that the convention used here are ones from my own head sprinkled with a bit of "iproute2" output format. Ill see if I can improve on this a bit moving forward. The explanation by another reply is correct :).

[lfmunoz4]

"jumping over the default linux network stack". What are the use cases. What are typical reasons to want to do that, what are benefits and downsides? What are the alternatives.

[mordechai9000]

I really don't know, but the first thing that occurred to me was implementing a "bump in the wire" type firewall. IE, one that sits on the network transparently and can filter and log traffic without affecting layer 2 or 3 headers.

I have no idea if this is an effective and performant approach, but it sounds feasible. Same with implementing switching or routing functionality.

[atmosx]

By skimming through, it is obvious that require familiarity with linux network namespaces and docker/kubernetes networking stack (virtual interfaces and what-not).

I don't blame the author though. When you write a technical post, at a certain point you need to assume the readership has some level of context otherwise you'll never complete the post.

[ldelossa]

Yes, you are right here. It's always difficult to know how far down the tree of topics you should go to provide a end-to-end explanation. I tried to call this out in the start of the article. These are the "hard parts" of technical writing IMO.

[yjftsjthsd-h]

I sometimes put a list at the top, like "This article assumes that you have a working familiarity with Linux namespaces (link to 3rd party intro to that), veth interfaces (link to 3rd party intro to that), [...]."

[ldelossa]

Good tip

[lelanthran]

Veth = virtual ethernet interface?

Veth1@2 virtual interface 1 in network 2 namespace.

Netns_1 = network namespace 1.

Just guessing based on context.

[lmz]

The @1 and @2 are the two "ends" of the veth. As described in the text they resemble pipes or a wire.