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?
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 :).
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.
Veth1@2 virtual interface 1 in network 2 namespace.
Netns_1 = network namespace 1.
Just guessing based on context.
Agree more practical examples but disagree this is too abstract.
I’m thinking starting at more common scenarios then jumping to container networking. Ie - Flow of a packet on a simple node, a two interface node, then namespaces, and then quirky virtual stuff.
Another example - I’d love to see how iptables actually works. Maybe how to use ebpf to implement iptables things like source/dest NAT, Masquerade, etc.
But yeah I learned a ton here. Thanks
If you're actually interested in iptables the old packet filter how-to is great:
https://www.netfilter.org/documentation/HOWTO/packet-filteri...
But iptables is turning into just a legacy interface for nftables in modern Linux. See eg:
I'm curious if you had reasons to not use veth in noarp mode.
Source: ChatGPT
