Overcoming Ephemeral Port Exhaustion in NGINX and NGINX Plus
Overcoming Ephemeral Port Exhaustion in NGINX and NGINX Plus NGINX and NGINX Plus are extremely powerful HTTP, TCP, and UDP load balancers. They are very efficient at proxying large bursts of requests and maintaining a large number of concurrent connections. In general these characteristics make NGINX and NGINX Plus particularly vulnerable to ephemeral port exhaustion. (Both products have this issue, but for the sake of brevity we’ll refer just to NGINX Plus for the remainder of this blog.) In this blog, we discuss the components of a TCP connection and how its contents are decided before a connection is established. We then show how to determine when NGINX Plus is being affected by ephemeral port exhaustion. Lastly, we discuss strategies for combatting those limitations using both Linux kernel tweaks and NGINX Plus directives. A Brief Overview of Network Sockets When a connection is established over TCP, [ more… ]
