TCP listen-queue dropping connections
/proc/net/netstat TcpExt ListenOverflows or ListenDrops is incrementing; the kernel is dropping arriving connections at accept-queue level. Either the application can't accept() fast enough or net.core.somaxconn is too small for the offered load.
Remediation
When this rule fires on one of your servers, the dashboard alert detail page renders the full remediation guidance: the command to run, what to verify after, and Furnace's annotation for your specific distro + hardware. Sign in at app.glassmkr.com to see the live alert.