Configure the sqlnet. ora file in Oracle

DBAs must be familiar with this file. What you know most is that sqlnet. ora is used to determine how oracle parses strings that appear in a connection, such as sqlpluss.

DBAs must be familiar with this file. What you know most is that sqlnet. ora is used to determine how oracle parses the strings that appear in a connection, such as sqlplus s.

DBAs are not familiar with this file. What everyone knows most is that sqlnet. ora is used to determine how Oracle parses the strings that appear in a connection. For example:
Sqlplus sys/oracle @ orcl
So how to resolve this orcl? If your sqlnet. ora is configured as follows:
SQLNET. AUTHENTICATION_SERVICES = (CNT)
　　
NAMES. DIRECTORY_PATH = (TNSNAMES, HOSTNAME)
Then, the client will first be in tnsnames. orcl records in the ora file. if there is no corresponding record, try to use orcl as a host name, resolve its ip address through the network, and then connect to the instance GLOBAL_DBNAME = orcl on this ip address, of course, here, orcl is not a host name.
　　
If I look like this
　　
NAMES. DIRECTORY_PATH = (TNSNAMES)
　　
Then the client will only search for orcl records from tnsnames. ora
Today, let's take a closer look at the configuration of parameters in sqlnet. ora and their respective meanings.
According to the official documentation, sqlnet. ora has so many functions:
Specify the client domain to append to unqualified names
Prioritize naming methods
Enable logging and tracing features
Route connections through specific processer
Configure parameters for external naming
Configure Oracle Advanced Security
Use protocol-specific parameters to restrict access to the database
Important parameters and explanations:
1. BEQUEATH_DETACH
Controls the signal handling switch in unix systems. The default value is no, that is, signal handling is enabled.
2. DEFAULT_SDU_SIZE
Specify the size of session data unit (SDU), in bytes. We recommend that you set this parameter on both the client and server to ensure that the same SDU size is used for the link, if the configuration values of the client and server do not match, a small value is used.
3. LOG_DIRECTORY_CLIENT/LOG_DIRECTORY_SERVER
Specify the location of log files on the client or server
4. NAMES. DEFAULT_DOMAIN
Set the domain in which the client resolves the name
5. NAMES. DIRECTORY_PATH
Specifies the order of client name resolution methods. The default value is NAMES. DIRECTORY_PATH = (tnsnames, onames, hostname)
Optional values: tnsnames, ldap (dictionary server), hostname/ezconnect, cds (in a distributed environment), and nis (Network Information Service (NIS)
6. SQLNET_ALLOWED_LOGON_VERSIONS
SQLNET_ALLOWED_LOGON_VERSIONS = (10, 9, 8)
7. SQLNET. AUTHENTICATION_SERVICES
Specify to start one or more authentication services
Authentication Methods Available with Oracle Net Services:
None for no authentication methods. A valid username and password can be used to access the database.
All for all authentication methods
ETS for Windows NT native authentication
8. SQLNET. INBOUND_CONNECT_TIMEOUT
Specifies the timeout time when no connection is established on the client. After timeout, oracle will interrupt the connection and report an error.
9. SSL_VERSION
Version of the specified ssl Link
10. TCP. EXCLUDED_NODES
Specifies a node that is not allowed to access oracle. The host name or IP address can be used.
11. TCP. INVITED_NODES
Specifies the client that allows access to the database. The priority is higher than TCP. EXCLUDED_NODES.
12. TCP. VALIDNODE_CHECKING
Use this parameter to enable the preceding two parameters.
13. TNSPING. TRACE_DIRECTORY
Use this parameter to specify the directory of the tnsping trace file. The default value is the $ ORACLE_HOME/network/trace directory.
For more parameter information, see Oracle Database Net Services Reference.