What is an SMB Port? A Detailed Description of Ports 445 + 139 | UpGuard

This report provides an overview of the SMB protocol (history, dialects, and operation), explains the role of ports 139 and 445, outlines security risks including the EternalBlue exploit and WannaCry ransomware outbreak, and gives practical mitigation recommendations (patching, firewalls, VPNs, VLANs, and avoiding public exposure of SMB ports).