netsec people for once i am asking for a reply here. tell me why IPsec is so hateful. tell me there's some heinous story about it literally escaping a research lab at cisco in the early 90s by accident
— 🎃Utterly dispassionate documentary hog slaughte🎃 (@gravislizard) October 22, 2019
I’ve gotten many, many IPsec tunnels working and it does bite ass. The reason is that it’s a protocol (really a suite of associated-ish protocols and specifications) that has been in development, and thus ever-changing, since the 1970s.
And it’s all terrible because IPsec is designed to cover too many use cases and its actual implementation is up to dozens of different firewall vendors and OS makers, many of which don’t follow the RFCs or do it in such a confusing way that their interface or CLI is basically unusable. Additionally, since IPsec has been around so long, it’s not unusual to find firewalls or other devices still very much in service that can’t talk to newer devices because the old ones don’t support — or properly support — newer, now-required (by corporate policy) features. For instance, at work I have a firewall that is less than five years old that we could not initially use to connect to a client as it didn’t support IKEv2.
Anyway, IPsec is terrible because it’s trying to cover a huge territory with open source solutions which receive very little quality development, and because IPsec has been around so long there are 900 poor implementations of nearly-identical features, none of which play that well together for various reasons.