BGP announces reachability, not truth
The internet's routing system works largely on announcements being believed.
A network says it can reach a range of addresses and others accept it. There is no inherent verification, which is why misconfigurations propagate globally within minutes and why hijacks are possible at all. It is one of the more unsettling facts about the internet: a great deal of it runs on operators mostly behaving and mostly filtering.
More on Internet routing
- BGP hijacking can redirect traffic before applications see itThe points move under the train
- Route leaks can be accidental and disruptiveThe whole motorway down a side lane
- RPKI validates route origins, not the whole pathOnly the first pair of hands is signed for
- More specific Internet routes usually winThe narrower claim takes it
- Anycast sends one address to multiple placesOne address, many doorsteps
- Route filtering is Internet hygieneWe all drink from the same main