sql connection taking ages when using IP Address vs Computer Name

[Wallace Turner]

Hi All (especially Greg Low tho), I've been debugging an issue whereby conn.Open( ) was/is taking 5 seconds to connect to a machine on the LAN (same VM host actually)         I've 'fixed' this by changing the connection string.  Was: database=FooDb;server=10.210.10.130;trusted_connection=true; //takes 5 seconds to conn.Open( ) and changed to: database=FooDb;server=sql-svr;trusted_connection=true; //takes 30ms seconds to conn.Open( ) This behavior is consistent on subsequent runs (it is just a simple console app). You don't even need to query anything which proves its nothing to do with a specific query. Why does this cause an issue? Well if the application is idle for 5 minutes then the next person to 'do something' has to wait 5 secs for the sql conn to open. Someone care to explain?