I’m in a case where my connection to the database server is very slow. Currently, I’m using SSMS to connect to it by IPAddress and Port.
The connection string looks like this: IP_address, portInstance name.
This takes about 10-12 seconds to connect, any actions such as expanding tables, querying, or just simply clicking would take the same amount of time.
If I follow these 2 methods, it connects super fast as if I were connecting to the local database.

• Adding these 2 into hosts file:

127.0.0.1    crl.microsoft.com
<IP address of db server>  <random name> 

• Or just simple connect to the server by format Servername,portInstanceName instead

ProServer,14494PRO_DEMO_S1

Additional information I think may help to troubleshoot this issue:

• DBServer and my computer are on 2 different VMs, connecting by RDP.
• Only my VMs connect to the DBServer, all were stopped for troubleshooting the issue.
• Connecting by using sqlcmd would have the same issue. 4-5 seconds with IPAddress, <1 second with the server name.
• The DB server is just freshly setup, there is no heavy query running.
• The DB Server is not overloaded, both CPU, Ram usage seem good.