How Are SQL Server Clients Connecting?
I believe we have several misunderstandings here, so lets try to sort them out one by one and see if that clarifies the big picture in the end.
What you refer to as an &quot;unnamed instance&quot; is what we call a default instance. Just as FYI.
It is not the first installed instance that get port 1433. 1433 is a Well Known Port for the default instance. This is from back in the days when we couldn't have more than one instance (pre-SQL Server 2000).
A named instance get a port number from the Windows dynamic range at first startup. &quot;Dynamic&quot; does not mean a different port number at every startup. The assigned port is stored in the registry and is attempted to be used at following startups. &quot;Dynamic&quot; controls what happens if that fails (i.e., the port last used is now busy). &quot;Dynamic&quot; means &quot;get a different port from Windows&quot;. The other option means &quot;fail to start SQL server&quot;.
What you see in the GUI you posted as an IP being &quot;disabled&quot; is bad GUI presentation. The individual IP sections are being overridden by the bottom-most config (IPAll). Having a port there means all IP addresses are using that port (as far as I understand). Readers are welcome to comment/edit here.
As for your named instance, I suggest you set the port number under IPAll to 0 (and have nothing for the &quot;static port&quot;) and re-start your SQL Server. It should now get a new port from the dynamic Windows range.