Go to the root of the DotNetNuke install and open the “Default.aspx.vb” file. Find the code:

‘ tab title override
If PortalSettings.ActiveTab.Title <> “” Then
strTitle = PortalSettings.ActiveTab.Title
End If
Title = strTitle

and change this to include the portal name with “PortalSettings.PortalName”:

‘ tab title override
If PortalSettings.ActiveTab.Title <> “” Then
strTitle = PortalSettings.PortalName & ” – ” & PortalSettings.ActiveTab.Title
End If
Title = strTitle

This may change with later versions of DNN (such as 5) but this works in 4. Why this isn’t the default setting I have no idea.