Quick Beginnings for DB2 Extended Enterprise Edition for UNIX
This section assumes that TCP/IP is functional on the client and DB2
server workstations. See "Software Requirements" for the communication protocol requirements for your platform. See "Possible Client-to-DB2 Server Connectivity Scenarios" for the supported communication protocols for your particular client and
server.
The following steps are required to set up a DB2 client to use TCP/IP
communications:
- Identify and record parameter values.
- Configure the client:
- Resolve the server's host address.
- Update the services file.
- Catalog the TCP/IP node.
- Catalog the database.
- Test the connection between the client and server.
|
Due to the characteristics of the TCP/IP protocol, the TCP/IP subsystem may
not be immediately notified of the failure of a partner on another
host. As a result, a client application accessing a remote DB2 server
using TCP/IP, or the corresponding agent at the server, may sometimes appear
to be hung. DB2 uses the TCP/IP SO_KEEPALIVE socket option to detect
when there has been a failure and the TCP/IP connection has been
broken.
If you are experiencing problems with your TCP/IP connection, refer to the
Troubleshooting Guide for information on this parameter and other common TCP/IP problems.
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As you proceed through the configuration steps, complete the
Your Value column in the following table. You can fill in
some of the values before you start configuring this protocol.
Table 13. TCP/IP Values Required at the Client
| Parameter
| Description
| Sample Value
| Your Value
|
| Hostname (hostname)
or
IP address (ip_address)
|
Use the hostname or ip_address of the remote server
workstation.
To resolve this parameter:
- Issue the hostname command at the server to obtain the
hostname parameter.
- Issue the ping server_hostname command to obtain the
ip_address parameter.
| serverhost
or
9.21.15.235
|
|
|
Connection Port
- Connection Service name (svcename)
- Port number/Protocol (port_number/tcp)
|
Values required in the services file.
The Connection Service name is an arbitrary name used to represent the port
number (port_number) on the client.
The port number for the client must be the same as the port number that the
svcename parameter maps to in the services file at the
server. (The svcename parameter is located in the database
manager configuration file on the DB2 server.) This value must not be
in use by any another applications, and must be unique within the
services file. Ensure that you do not specify a port number
that is being used by the Fast Communication Manager (FCM).
|
server1
3700/tcp
|
|
| Node name (node_name)
|
A local alias, or nickname, that describes the node where the database
resides. You can choose any name you want, however, all node name
values within your local node directory must be unique.
| db2node
|
|
The following steps describe how to configure this protocol
on the client. Replace the sample values with your worksheet
values.
|
If your network has a name server, or you are planning to directly specify
the IP address (ip_address) of the server, skip this step and proceed
to "Step B. Update the Services File".
|
The client workstation must know the address of the server to which it is
attempting to establish communications. If a name server does not exist
on your network, you may directly specify a hostname that maps to the IP
address (ip_address) of the host in the local hosts
file. See Table 14 for the location of the hosts file for your
particular platform.
| If you are planning on supporting a UNIX client that is using Network
Information Services (NIS), and you are not using a name server on your
network, you must update the hosts file located on your NIS master
server.
|
Table 14. Location of the Local Hosts and Services Files
| Platform
| Location
|
| Macintosh
|
The hosts file is located in the folder called System
Folder.
| Note: | This operating system does not use a services file. You
must catalog this node using the Port_number parameter. See "Step C. Catalog the TCP/IP Node" for more information.
|
|
| OS/2
| Specified by the etc environment variable.
Issue the set etc command to determine the location of your
local hosts or services files.
| Note: | For DOS and WIN-OS2 sessions, you might need to update the hosts
and services files located in the tcpip_product\dos\etc
directory.
|
|
| Windows 3.x
| Typically in the tcpip_product\etc directory, but it depends
on the products that you have installed.
Refer to your TCP/IP documentation for more information.
|
| Windows 95
| windows directory
|
| Windows NT
| winnt\system32\drivers\etc directory
|
| UNIX
| /etc directory
|
Using a local text editor, add an entry to the client's
hosts file for the server's hostname. For
example:
9.21.15.235 serverhost # host address for serverhost
where:
- 9.21.15.235
- is the ip_address
- serverhost
- is the hostname
- #
- is a comment describing the entry
Notes:
- If the server is not in the same domain as the client, you must provide a
fully qualified domain name such as
serverhost.vnet.ibm.com, where
vnet.ibm.com is the domain name.
- For specific information on resolving host addresses, refer to your
TCP/IP documentation.
Using a local text editor, add the Connection Service name and port number
to the client's services file for TCP/IP support.
For example:
server1 3700/tcp # DB2 connection service port
where:
- server1
- is the Connection Service name
- 3700
- is the port number for the Connection Port
- tcp
- is the communication protocol that you are using
The port number used on the client must match the port number used on the
server.
|
If you are planning on supporting a UNIX client that is using Network
Information Services (NIS), you must update the services file
located on your NIS master server.
The file called services is located in the same directory as the
local hosts file that you may have edited in "A. Resolve the Server's Host Address".
Ensure that you did not specify a port number that is being used by the
Fast Communication Manager (FCM) or any other process.
See Table 14 for the location of the services file for your particular
platform.
|
You must add an entry to the client's node directory
to describe the remote node.
This entry specifies the chosen alias (node_name), the
hostname (or ip_address), and the svcename (or
port_number) that the client will use to access the remote
server.
To catalog the TCP/IP node, perform the following steps:
- Log on to the system as a user with System Administrative (SYSADM) or
System Controller (SYSCTRL) authority.
- If you are using a UNIX client, set up the instance environment and invoke
the DB2 command line processor as follows:
- Run the start up script as follows:
. INSTHOME/sqllib/db2profile (for Bourne or Korn shell)
source INSTHOME/sqllib/db2cshrc (for C shell)
where INSTHOME is the home directory of the instance.
- Start the DB2 command line processor by issuing the db2
command.
- Catalog the node by issuing the following commands in the command line
processor:
catalog tcpip node node_name remote [ hostname | ip_address ] server [ svcename | port_number ]
terminate
For example, to catalog the remote server serverhost on the node
called db2node, using the service name server1, use:
catalog tcpip node db2node remote serverhost server server1
terminate
To catalog a remote server with the IP address
9.21.15.235 on the node called db2node,
using the Port number 3700, use:
catalog tcpip node db2node remote 9.21.15.235 server 3700
terminate
|
If you need to change values that were set with the catalog node
command, first run the uncatalog node command in the command line
processor as follows:
uncatalog node node_name
Recatalog the node with the value that you want to use.
|
Before a client application can access a remote database, the database must
be cataloged on the server node and on any client nodes that will connect to
it. When you create a database, it is automatically cataloged on the
server with the database alias (database_alias) the same as the
database name (database_name). The information in the database
directory, along with the information in the node directory, is used on the
client to establish a connection to the remote database.
To catalog a database on the client, perform the following steps.
- Log on to the system as a user with System Administrative (SYSADM) or
System Controller (SYSCTRL) authority.
- Fill in the Your Value column in the following
worksheet.
Table 15. Parameter Values for Cataloging Databases
| Parameter
| Description
| Sample Value
| Your Value
|
| Database name (database_name)
| The database alias (database_alias) of the remote
database. When you create a database, it is automatically cataloged on
the server with the database alias name (database_alias) the same as
the database name (database_name).
| sample
|
|
| Database alias (database_alias)
| An arbitrary local nickname for the remote database, on the
client. If you do not provide one, the default is the same as the
database name (database_name). This is the name that you use
when connecting to a database from a client.
| tor1
|
|
| Node name (node_name)
| The name of the node directory entry that describes where the database
resides. Use the same value for node name (node_name) that you
used to catalog the node in the previous step.
| db2node
|
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- If you are using a UNIX client, set up the instance environment and invoke
the DB2 command line processor as follows:
- Run the start up script as follows:
. INSTHOME/sqllib/db2profile (for Bourne or Korn shell)
source INSTHOME/sqllib/db2cshrc (for C shell)
where INSTHOME is the home directory of the instance.
- Start the DB2 command line processor by issuing the db2
command.
- Catalog the database by issuing the following commands in the command line
processor:
catalog database database_name as database_alias at node node_name
terminate
For example, to catalog a remote database called sample so that
it has the alias tor1, on the node db2node, use:
catalog database sample as tor1 at node db2node
terminate
|
If you need to change values that were set with the catalog
database command, first run the uncatalog
database command in the command line processor as
follows:
uncatalog database database_alias
Recatalog the database with the value that you want to use.
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When the configuration of the server and client is complete,
use the following steps to verify that you can access data from a remote
database:
|
You will need to connect to a remote database to test the
connection. If you do not have a database on the server, create the
sample database on the server to test the connection. See "Creating the Sample Database" for more information.
|
- Start the database manager by issuing the db2start command on
the server (if it was not automatically started at boot time).
- Enter the following command in the client's Command Center or command
line processor to connect the client to the remote database:
connect to database_alias user userid using password
The values for userid and password must be valid for the
system on which they are authenticated. By default, authentication
takes place on the SERVER. If the database manager is configured for
CLIENT authentication, the userid and password must be valid
on the client.
If the connection is successful, you will get a message showing the name of
the database to which you have connected. You are now able to retrieve
data from that database. For example, to retrieve a list of all the
table names listed in the system catalog table, enter the following SQL
command in the Command Center or command line processor:
"select tabname from syscat.tables"
When you are finished using the database connection, enter the connect
reset command to end the database connection.
If the connection fails, check the following items:
At the server:
- The db2comm registry value includes the value
tcpip. DB2COMM can be set in the db2profile or
db2cshrc file.
- The services file was updated correctly.
- The service name (svcename) parameter was updated correctly in
the database manager configuration file.
- The database was created and cataloged properly.
- The database manager was stopped and started (enter the db2stop
and db2start commands on the server).
- Ensure that you did not specify a port number that is being used by the
Fast Communication Manager (FCM) or any other process.
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If there are problems starting a protocol's connection managers, a
warning message is displayed and the error messages are logged in the
db2diag.log file, located in the instance
directory.
Additionally, any failure encountered while executing the
db2start command is logged to a time-stamped file in the log
subdirectory within the instance directory. This file contains the
db2start results from each database partition server in the
instance.
If there is no error when the db2start command is run, these
files are removed.
Refer to the Troubleshooting Guide for information on the db2diag.log file.
|
At the client:
- If used, the services and hosts files were updated
correctly.
- The node was cataloged with the correct hostname (hostname) or IP
address (ip_address).
- The port number must match, or the service name must map to, the port
number used on the server.
- The node name (node_name), specified in the database directory,
points to the correct entry in the node directory.
- The database was cataloged properly, using the server's
database alias (database_alias) that was cataloged when the database
was created on the server, as the database name (database_name) on
the client.
After you verify these items, refer to the Troubleshooting Guide if the connection still fails.
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