How we found a bug in Amazon ELB

Post by narsil » Wed, May 04, 2016, 12:17 AM UTC

colmmacc wrote: post #37

narsil wrote: post #28

We recently discovered that the NAT Gateway also terminates connections by issuing a RST packet when it receives the next packet for a connection that it believes to have timed out, effectively causing the new request to fail. The previous recommended approach of NATing in VPC was to use NAT instances, which sent FIN packets when the timeout was hit, cleanly closing the connection. That behavior was far better, since…

Full disclosure: I'm an engineer at AWS and I work on NAT Gateway :) Thanks for the pointer to urllib3 - we'll take a look at it and see if there's anything we can do about the behavior. One of the challenges with sending "FIN" on timeout is, as you write ... it closes the connections cleanly. Some TCP based protocols (Including even HTTP in some modes) use a successful connection close to indicate that an object has…