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Windows Server Failover Clustering/SQL Server Firewall Access Rules Last updated: 2026-08-21 17:01:33 This document defines the firewall rules necessary for a Multi-Subnet Windows Server Failover Cluster (WSFC) environment. It covers WSFC core communication, the WSFC dependency on Active Directory (AD), and SQL Server Availability Group (AG) communication. Use these rules when you request network access for a Multi-Subnet Cluster. This version corrects several rows to agree with current Microsoft documentation. See Verification Notes at the end of this document for the list of changes and sources. Table of Contents Windows Server Failover Clustering/SQL Server Firewall Access Rules Table of Contents Best Practice: IP Specificity Critical Action: Review Ephemeral Port Ranges Section 1: Core WSFC and Active Directory Ports Section 2: SQL Server Database Engine and Availability Group Ports Section 3: SQL Server BI Stack Ports (Conditional) Section 4: Multi-...

This document defines the firewall rules required for a Multi-Subnet Windows Server Failover Cluster (WSFC) environment. It covers WSFC core communication, the WSFC dependency on Active Directory (AD), and SQL Server Availability Group (AG) communication. Use these rules when you request network access for a Multi-Subnet Cluster. This version corrects several rows to agree with current Microsoft documentation. See Verification Notes at the end of this document for the list of changes and sources. Table of Contents Best Practice: IP Specificity Critical Action: Review Ephemeral Port Ranges Section 1: Core WSFC and Active Directory Ports Section 2: SQL Server Database Engine and Availability Group Ports Section 3: SQL Server BI Stack Ports (Conditional) Section 4: Multi-Subnet / Cloud Deployment Ports (Conditional) Section 5: Official References Verification Notes Windows Server 2025 / SQL Server 2025 Notes Best Practice: IP Specificity Specify exact IP ad...

Requirements for SQL Server AlwaysOn Feature on a Windows Server Failover Cluster.md This document targets Windows Server 2022 and SQL Server 2022. See Update Notes at the end of this document. That section lists what changed from the original 2012 version, and the reason for each change. Table of Contents Overview Terminology Windows Server Failover Clustering (WSFC) Cluster Name Object (CNO) Virtual Computer Object (VCO) Symmetric / Asymmetric Storage SQL Server Failover Clustered Instance (FCI) SQL Server Failover Clustered Instance CNAME (FCI CNAME) SQL Server Availability Group (AG) SQL Server Availability Group Listener (AGL) SQL Server Availability Group Listener CNAME (AGL CNAME) WSFC Requirements SQL Server FCI Requirements SQL Server Availability Group Requirements Update Notes Windows Server 2025 / SQL Server 2025 Notes Overview This document covers the SQL Server AlwaysOn feature. This includes the Failover Clustered Instance, the A...