We were doing audit and discovered that our always on listener was configured with port 14333 (yes! extra 3). We were curious how our applications are able to connect given that their connection string references port 1433. We would have expected 1433 connections to fail since listener is 14333.
This is not a named instance and we do not have the SQLbrowser service running.
Can anyone explain why both ports 1433 & 14333 work?
sqlcmd -S agd-sqlfoo_listener_name,1433 # Connection established
sqlcmd -S agd-sqlfoo_listener_name,14333 # Connection established
sqlcmd -S agd-sqlfoo_listener_name,143 # Connection fail as expected
sqlcmd -S agd-sqlfoo_listener_name,1234 # Connection fail as expected
Queryoutput from sys.dm_exec_connections
connect_time net_transport protocol_type endpoint_id auth_scheme local_net_address local_tcp_port
2016-09-23 14:24:30.063 TCP TSQL 4 NTLM 172.17.35.16 14333
2016-09-23 13:03:29.317 TCP TSQL 4 NTLM 172.17.35.16 1433
2016-09-23 14:33:57.110 TCP TSQL 4 NTLM 172.17.35.16 1433
2016-09-23 08:48:57.230 TCP TSQL 4 NTLM 172.17.35.16 1433
2016-09-23 08:51:03.353 TCP TSQL 4 NTLM 172.17.35.16 1433