Counts the number of times TCP connections made a direct transition from CLOSED to SYN-SENT, meaning connections this device itself initiated. Because this only counts outbound-initiated connections, a rise here reflects the gateway itself opening new TCP sessions, to a log server, an update server, or a management console, so a spike unrelated to any known admin action is worth investigating as possibly unexpected outbound activity from the box itself. Example: tcpActiveOpens jumping at 2am with no scheduled job configured for that time would be worth checking against what process on the gateway initiated those connections.