SQL server 2025 Enterprise Developer edition connection

Question

I installed a new SQL server 2025 Enterprise developer edition for our development environment. this is our first 2025 instance. I can connect to the server and database using a SSMS installed locally on the server, but cannot connect to it use my laptop in same network.
I enabled the TCP/IP protocol in the SQL server network configuration but still cannot connect from my laptop. My laptop can connect to other 2022 SQL servers on same network without an issue.
I checked with AI, it says I need to add inbound rule for windows defender firewall, but I remember I never need to do this before in previous version. I wonder if this is a feature of Enterprise developer edition?

If so what process we need to do, any online microsoft doc about this?

Thanks,

Answer 1

No, this is nothing new in SQL 2025, but it is the same connection blues as with any version or edition.

First question: You did restart SQL Server after you enabled TCP/IP, didn't you?

Next question: Is this a default instance or a named instance? In the latter case, you must also make sure that the Brower service is running.

And, yes, you need to make sure that your firewall accepts connections on the port that SQL Server is listening on. And for named instances, port UDP 1434 must also be open.

What is the exact error message you get?

As for Microsoft documentation, they have this troubleshooter for connection problems.

Answer 2

No. This is not a SQL Server 2025 Enterprise/Developer-edition-specific feature.

For SQL Server Developer, Express, and Evaluation editions, remote access is not enabled by default when first installed, and connecting from another computer requires:

1. A network protocol enabled
   • In SQL Server Configuration Manager → SQL Server Network Configuration → Protocols for <InstanceName>
   • Enable TCP/IP.
2. Firewall access allowed
   • If Windows Firewall is in use, inbound traffic must be allowed either by:
     • opening the SQL Server TCP port, or
     • creating a program rule for sqlservr.exe.
3. Correct port/instance handling
   • A default instance typically uses TCP 1433.
   • A named instance such as many non-default installs can use dynamic ports.
   • For named instances, Microsoft recommends using a fixed/static port because dynamic ports can change each time the Database Engine starts, which makes firewall configuration harder.

A practical path for the scenario described:

1. Confirm the instance type
   • If this is the default instance, connect from the laptop using ServerName.
   • If this is a named instance, verify the exact instance name.
2. If TCP/IP was just enabled, restart the SQL Server service
   • The protocol change must be active before remote clients can use it.
3. Add a firewall rule
   • Open Windows Firewall with Advanced Security by running wf.msc.
   • For a fixed-port configuration:
     1. Inbound Rules → New Rule
     2. Select Port
     3. Select TCP
     4. Enter the SQL Server port, such as 1433 for a default instance
     5. Select Allow the connection
     6. Select the applicable profiles
     7. Finish the rule
   • For dynamic-port or named-instance scenarios, a Program rule for sqlservr.exe is an alternative:
     • Typical path example: C:\Program Files\Microsoft SQL Server\MSSQL<VersionNumber>.<InstanceName>\MSSQL\Binn\sqlservr.exe
4. Test with explicit server and port if needed
   • If the instance is not listening on 1433, test using:
     • <servername>,<portnumber>
   • If that works, the connection string should use the server name plus port.
5. Limit firewall scope where possible
   • Opening the rule to Any computer is not recommended.
   • Prefer My network (subnet) only or a Custom list to reduce exposure.

Important security note: opening firewall ports increases exposure to malicious traffic, so restrict scope where possible.

Microsoft documentation for this process exists and covers:

• enabling TCP/IP for remote connections,
• opening a TCP port in Windows Firewall,
• using a program rule for sqlservr.exe,
• and the recommendation to use a fixed port for named instances.

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References:

• Lesson 2: Connect to the Database Engine from another computer
• Configure the Windows Firewall to allow SQL Server access
• Configure Windows Firewall for Database Engine access
• A network-related or instance-specific error occurred while establishing a connection to SQL Server