Proxy's memory regulation.

Products

• ISG Proxy
• ProxySG Software - SGOS

Issue/Introduction

This article explains when the proxy will get into a memory regulation state.

 

Resolution

By default, there is an 'Upper Limit' on the memory usage (typically 80%) and a 'Lower Limit' on the memory usage (typically 75%).
When the proxy memory reaches the 'Upper Limit', the box goes into memory regulation mode but not until the memory usage goes below the 'Lower Limit', does the proxy go out from the memory regulation state.
 
When the proxy is in memory regulation mode, the proxy will stop accepting new connections. The acceptor for that service will then become blocked.  The socket for the acceptor can only queue so many connections in the listen queue. When the queue hits the limit, any new SYN packet coming in will be reset (rejected), and the statistics 'TCP2.72' which is the 'Number of TCP listen queue overflows' will get incremented.