Beyond 'It Works on My Machine': Solving Docker Networking & DNS Bottlenecks

This guide addresses production-grade Docker networking issues including DNS resolution traps caused by ndots and search domain configurations, Node.js's lack of default DNS caching leading to EAI_AGAIN errors, and MTU mismatches between AWS EC2 instances and Docker networks that cause packet loss. Solutions include using FQDNs with trailing dots, implementing DNS caching with custom HTTP agents and keep-alive connections, and aligning MTU settings across network layers.