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dalms's avatar
dalms
Copper Contributor
Jan 20, 2025
Solved

SQL Cluster Connecting to Linked Server over a firewall.

Hi,

Scenario:

SQL FCI Cluster --> firewall (stateful) --> SQL Linked Server

SQL cluster needs to connect to linked server at the other side of a firewall.  

Question:

What needs to be opened on the firewall?

SQL VIP -->  SQL VIP

or are the cluster node IP's required too?

SQL VIP -->  SQL VIP
Node1 --> SQL VIP
Node2 --> SQL VIP

Many thanks

Cluster
firewall
Linked Server
sql
  • petevern's avatar
    petevern
    Jan 25, 2025

    I would request to open all 3 as have seen cases using failover that the actual node is initiating the connection.

    Source:

    SQL Server VCO IP
    Node 1 IP
    Node 2 IP

    Destination

    SQL VIP (linked server)

    Port

    Normally 1433 but can also be a dynamic port so something to check.

2 Replies

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  • petevern's avatar
    petevern
    Brass Contributor
    Jan 25, 2025

    I would request to open all 3 as have seen cases using failover that the actual node is initiating the connection.

    Source:

    SQL Server VCO IP
    Node 1 IP
    Node 2 IP

    Destination

    SQL VIP (linked server)

    Port

    Normally 1433 but can also be a dynamic port so something to check.

    • dalms's avatar
      dalms
      Copper Contributor
      Jan 28, 2025

      Our testing has found the same.  The cluster VIP is only used for incoming connections.  Thanks Petevern.

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