3 ms·

what's an AS?

• chatmasta 9y ago
  AS = Autonomous System (see Wikipedia). This is the corporation or entity to which an IP prefix (min /24) is registered, and which shows up in queries on sites like ipinfo.io. BGP Path to Target IP prefix = ordered list of autonomous systems to reach target IP prefix The point of BGP is to find the shortest AS path to an IP. Each AS has at least one router, and each router has at least one other AS peer. A router will forward the packet as far as it can given the peers it knows, until the AS list is length 0, at which point the controlling AS routes traffic to its destination.
• notriddle 9y ago
  Autonomous System. Basically, a top level Internet shard. You need to become a Real ISP to pull off this attack.
  • chatmasta 9y ago
    That may be technically true, but not by any layman’s definition of an ISP. An AS can be a tiny company (I’ve been one) as long as it has some IP space SWIPed (registered) to it with ARIN/RIPE. All you need is to fill out a form. Then you need to find other ASes to peer with you of course. Also note that technically all you need is the ability to advertise routes. That could be mutually exclusive from AS status if your server provider is willing to advertise routes from their AS on your behalf (like vultr does, I think). In that case the provider is acting irresponsibly and should validate the routes.