1688
Microsoft KMS
Low RiskTCP — System & Infrastructure
Port Overview
Port Number
1688
Service Name
Microsoft KMS
Transport Protocol
TCP
Category
System & Infrastructure
Security Risk
Low
Port Range
Registered (1024-49151)
What is Port 1688?
Port 1688 is used by Microsoft Key Management Service (KMS) for volume license activation of Windows and Office products. Organizations with volume licensing use a KMS server to activate multiple Microsoft products without individual product keys. This port must be accessible from all machines that need KMS activation.
TCP
System & Infrastructure
Commonly Used
Security Considerations
Port 1688 (Microsoft KMS) is classified as low risk. This service uses encryption or has a minimal attack surface, making it relatively safe to expose.
Recommendation: Standard security practices apply. Keep software updated and monitor access.