Listener on port 1434

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Listener on port 1434

Brian Brown-204626

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Points: 3211
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August 4, 2006 at 9:17 am

#68339

I need to verify that the listener for SQL Server if active and listening on port 1434. I have used the netstat command, and it will show the main port being used(1433 ususally), but it does not show this port. I have check on other servers(clustered and non-clustered) that sre accessed remotely and they do not show this port either. Is there a way to display the listener and ports that SQL Server is using?

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Lowell SSC Guru Points: 323518 More actions · Answer 1

i know the default UDP port is 1434, but could not find it anywhere in my registry;

i've pasted a script below that finds the TCPIP ports being used, but i don't know how to detect which UDP port is used.

[edited] SQL server always responds to UDP port 1434, regardless; it is similar to DNS, which is always port 53; the service must be known in order to use it, so i guess you trade a tiny bit of security, as it is vulnerable to attacks if the port is exposed via the firewall, as a trade fof for services provided.

CREATE TABLE #GetPort

(

token varchar(100),

value varchar(20))

go

DECLARE @inst varchar(200)

DECLARE @inst1 varchar(100)

--Determine registry path and key

IF(charindex('\',@@servername) > 0)

BEGIN

SELECT @inst = substring(@@servername,charindex('\',@@servername) ,50)

SELECT @inst = 'SOFTWARE\Microsoft\Microsoft SQL Server'+@inst+'\MSSQLServer\SuperSocketNetLib\Tcp'

--SELECT @inst1 = 'TcpDynamicPorts'

SELECT @inst1 = 'TcpPort'

END

ELSE

BEGIN

if SUBSTRING(@@VERSION,23,1) = '7'

begin

SELECT @inst = 'SOFTWARE\Microsoft\MSSQLServer\Client\SuperSocketNetLib\VIA'

SELECT @inst1 = 'DefaultServerPort'

end

else

begin

SELECT @inst = 'SOFTWARE\Microsoft\MSSQLServer\Client\SuperSocketNetLib\Tcp'

SELECT @inst1 = 'DefaultPort'

end

END

print @inst + '\\\\////'+ @inst1

INSERT #GetPort

EXEC master..xp_regread 'HKEY_LOCAL_MACHINE', @inst, @inst1

SELECT substring(@@servername,1,25) as ServerName, value as port FROM #GetPort

DROP TABLE #GetPort

Lowell

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Balmukund SSCertifiable Points: 6648 More actions · Answer 2

I always look into SQL ErrorLog to find the port on which my SQL Server is listening.

you can use sp_readerrorlog procedure to read errorlogs from query analyzer.

This should exist in registry key mentioned by Lowell.

HTH