Should port 3268 be open on my firewall?

Port 3268 should only be open with strict firewall rules whitelisting trusted IP addresses. Enable rate limiting and intrusion detection systems.

What transport protocol does port 3268 use?

Port 3268 (Microsoft Global Catalog) uses the TCP transport protocol and falls under the System & Infrastructure category.

:3268 (TCP)

Microsoft Global Catalog

Q: Is port 3268 (Microsoft Global Catalog) dangerous?

Port 3268 is classified as high risk. It is a common target for automated scanning and brute-force attacks. Restrict access to trusted IPs if exposure is necessary.

High Risk

TCP — System & Infrastructure

Port Overview

Port Number 3268

Service Name Microsoft Global Catalog

Transport Protocol TCP

Category System & Infrastructure

Security Risk High

Port Range Registered (1024-49151)

What is Port 3268?

Port 3268 is used by Microsoft Active Directory for the Global Catalog service, which provides a partial replica of all objects in the directory forest. LDAP clients query the Global Catalog to locate objects across multiple domains. This port is essential for cross-domain authentication in Windows enterprise environments.

TCP System & Infrastructure Commonly Used

Security Considerations

Port 3268 (Microsoft Global Catalog) is classified as high risk. This port is a common target for automated scanning and brute-force attacks. If you must expose it, restrict access to known IP addresses.

Recommendation: Use firewall rules to whitelist trusted IPs. Enable rate limiting and intrusion detection.

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