Pipelining Gotchas: Lessons from SMTP
2025-06-20
This article explores the pitfalls of pipelining in network protocols. In text-based protocols like SMTP, clients might send multiple requests without waiting for responses. However, improper server-side implementation can lead to issues. A server might rely on an implicit state machine, causing confusion when handling multiple concurrent requests, leading to incorrectly accepting or rejecting emails. The article analyzes the root cause of this potential problem and references RFC 2920's discussion of pipelining deadlocks, reminding developers to carefully handle pipelining to avoid errors due to improper state management or buffering issues.
Development
Network Protocols