title: Cannot establish a connection to SQL Server over VPN using TCP protocol
body: <p>During my daily work, I need to use the customer's Database. for this connection, first of all, I need to connect the VPN to customer's network, and then make the DB connection. </p>
  
  <p>Normally, if this connection can be established using TCP protocol. But  sometimes I cannot connect to the DB. Then I track the network package, I found the connection is attempting connect to customer's DB using UDP protocol. </p>
  
  <p>And now my network environment is using '172.16', if I change my network to '10.12', do the same connection, then change back to the '172.16' network, the connection can be established successfully. </p>
  
  <p>Because the DB is in customer's side, I cannot check it.</p>