A perfect solution for SQL Server connection failures

This article lists all possible causes of the network adapter cocould not establish the connection exception and provides a graphical troubleshooting wizard.
However, based on experience, it is most likely not to be upgraded to SP4. You can directly view Part 1.

Common Errors:The network adapter cocould not establish the connection
1. Check whether SQL Server allows remote access.
Procedure:
1) Open "Enterprise Manager", open the console root directory> SQL Server group> Database
2) Right-click the database and choose Properties"
 
3) Select the "connection" tab and check whether the RPC service is selected under "remote server connection.
2. Use the Telnet IP address 1433 to check whether the system prompts a connection error.
Such as telnet 127.0.0.1 1433
If a black screen is displayed, the port is normal.
If an error is prompted
Check whether the firewall shields the network access port of SQL Server or Java ide
If yes, disable the firewall and restart SQL Server and Java IDE for testing,
If the system still prompts the preceding error, perform the following steps:
3. Check the SQL server port number and whether the TCP/IP protocol is enabled.
Procedure:
1) Open "Enterprise Manager", open the console root directory> SQL Server group> Database
2) Right-click the database and choose Properties"
3) Select the "General" tab and click "network configuration". If no "TCP/IP protocol" is enabled, add it

4) Select "TCP/IP protocol" and click "properties" to check whether the port number is 1433.

5) If the port number is 1433, change it to another port number, modify the JDBC connection statement, and change the port number to the newly enabled port number, such as JDBC: Microsoft: sqlserver: // SERVER_NAME: 1400 (assuming the new port number is 1400)

4. Try each of the following methods:
1) check whether the SQL server connection is full.

2) for authentication issues.
Go to SQL audit ice Manager> specify server> content> Security. Change verification to SQL Server and windows.

3) Click properties to check whether the port is correct.
4) Run % mssql_home %/80/tools/binn/svrnetcn.exe.
Enable TCP/IP.
5) Turn off the firewall.

6) Update SQL Server to SP4:
Http://www.microsoft.com/downloads/details.aspx? Displaylang = ZH-CN & familyid = 8e2dfc8d-c20e-4446-99a9-b7f0109f8bc5
After my verification, it is generally easy to use to upgrade to SP4!
Pay attention to the upgrade method, instead of double-clicking to run it. This SP4 is the decompression program. You need to specify a directory. C:/is recommended. After decompression, you need to go to the directory to run the setup. bat is the real installation. I don't know why Microsoft doesn't directly call that. Do not understand !!!

The check method is as follows:

Execute the following SQL statement

Print @ version

For SP4, the following version number should appear:

Microsoft SQL Server 2000-8.00.2039 (Intel x86)
May 3 2005 23:18:38
Copyright (c) 1988-2003 Microsoft Corporation

Note that 8.00.2039

The information of other versions is as follows:

SQL Server 2000 version and level	@ Version	Product Level
Original SQL Server 2000 version	8.00.194	RTM
Database components SP1	8.00.384	SP1
Database components SP2	8.00.534	SP2
Database components SP3, sp3a	8.00.760	SP3
Ms de 2000 release	8.00.760	SP3
Database components SP4	8.00.2039	SP4

7) At last, be sure to note the differences between jdbc2.0 and 3.0.Http://www.java2000.net/viewthread.jsp? Tid = 367

8) in SQL Server 2005, if
Failed to connect to the host's TCP/IP. Java.net. connectexception: Connection refused: connect
Sqlserver2005 disables TCP/IP connections by default. How to start TCP/IP connection,
Open SQL Server Configuration Manager in the/Microsoft SQL Server 2005/configuration tool/directory, and select the MSSQLServer protocol,
Then there is a TCP/IP protocol in the window on the right, start it, stop the sqlserver service, and then start. The problem is solved.