We have a requirement to send encrypted traffic logs from our SRX-300 to our syslog server and Microsoft Sentinel. We are also questioning if we need the Juniper SRX Connector for Microsoft Sentinel.

Data Plane Logs over TLS explains how to configure logs over TLS, a connector is needed for MS Sentinel. For further details, please visit Microsoft Sentinel documentation. On the SRX end, the syslog configuration is very simple and is outlined on the link above.