type: u32 help: Maximum number of TCP half-open connections default: 512 val_help: u32:1-2147483647; Generic connection timeout in seconds syntax:expression: ($VAR(@) >= 1 && $VAR(@) <= 2147483647) ; "Value must be between 1 and 2147483647" update: sudo sysctl -q -w net/ipv4/tcp_max_syn_backlog=$VAR(@) delete: sudo sysctl -q -w net/ipv4/tcp_max_syn_backlog=512