Should port 1688 be open on my firewall?

Port 1688 is generally safe to have open. Apply standard security practices: keep software updated and monitor access logs.

What transport protocol does port 1688 use?

Port 1688 (Microsoft KMS) uses the TCP transport protocol and falls under the System & Infrastructure category.

:1688 (TCP)

Microsoft KMS

Q: Is port 1688 (Microsoft KMS) dangerous?

Port 1688 is classified as low risk. This service uses encryption or has a minimal attack surface, making it relatively safe to expose with standard security practices.

Low Risk

TCP — 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.

Related Ports — System & Infrastructure

0 Reserved 1 TCPMUX 2 Management Utility 3 CompressNET 4 Unassigned 5 RJE 6 Unassigned 7 Echo

Related Terms

Bandwidth Latency Packet Loss Ping Throughput ASN