It's really hard because it's often not really that your configuration is invalid. It's not a syntax error. It's that BGP provides a way for networks to tell ea

It's really hard because it's often not really that your configuration is invalid. It's not a syntax error. It's that BGP provides a way for networks to tell each other about how they see the world, and sometimes what you say can melt down everyone else's systems. It's a dynamic, constantly-changing system, and the effects of your actions may not always be seen - it's not always obvious how other networks behave and will react to your route announcements. And so even trying to snapshot the current state and say "hypothetically, would this change be a bad idea?" can be hard to get right. Now, this particular case was of internal BGP use at Cloudflare, so everything I said doesn't necessarily apply... but it still does a little. Even internal networks can be so complicated, they may as well be un-analyzable. I think the problems here are pretty deep, unfortunately, and have to do with our "network of networks" design.