Oracle Database: Checklist Connection Issues

BASLE BERN BRUGG DÜSSELDORF FRANKFURT A.M. FREIBURG I.BR. GENEVA
HAMBURG COPENHAGEN LAUSANNE MUNICH STUTTGART VIENNA ZURICH
Checklist: Database Connection Issues
Markus Flechtner

Trivadis – Our mission.
2 17.05.2022
Trivadis makes IT easier:
We provide significant support for our
customers in the smart use of data in
the digital age.
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Trivadis – What sets us apart.
3 17.05.2022
We understand the business processes and economic challenges of our customers and
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Our proven products, developed by Trivadis, are based on in-depth expertise in the key
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That sets us apart from the competition.
A selection of awards we have received
OPEN SOURCE

Trivadis – Our key figures
4 17.05.2022
Founded in 1994
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million)
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profitable

About me .. Markus Flechtner
Principal Consultant, Trivadis, Duesseldorf/Germany, since April 2008
Working with Oracle since the 1990’s
– Development (Forms, Reports, PL/SQL)
– Support
– Database Administration
Focus
– Oracle Real Application Clusters
– Database Upgrade and Migration Projects
Teacher
– O-RAC – Oracle Real Application Clusters
– O-NF-DBA – Oracle Database New Features for the DBA
– O-MT – Oracle Multitenant
– PG4ORA – PostgreSQL for Oracle DBAs
Blog:
https://markusdba.net/
@markusdba
17.05.2022 Checklist: Database Connection Issues
5

6
Technology on its own won't help you.
You need to know how to use it properly.

Agenda
7 17.05.2022
1. The trivial part: are the database and the listener running?
2. Check Network Infrastructure
3. Oracle Net Configuration
4. Try an Oracle Net Connection using Instant Client
5. Check Oracle Client Version
6. Check Password Versions
7. Oracle Net Logging & Tracing
8. Miscellaneous
9. More information

Before you start ..
8 17.05.2022
Has it ever worked before?
If yes, what was changed?
– "I changed nothing, I only improved some things .." 
Is the issue specific to a single client or a small set of clients?
– Local configuration issue?
– Same network segment => routing issue?
Are all clients affected?
– Server configuration issue?
– No routing to server?
– Central switch/firewall configuration?

9 17.05.2022
The trivial part

Check Database and Listener?
10 17.05.2022
Is the database instance running?
Is the (correct) listener running?
– Especially important when you have got multiple listeners running
– When a listener serves multiple database versions: listener should run with the highest
database version
Is the database instance registered with the (correct) listener?
– If LOCAL_LISTENER is not set => instance registers with listener on port 1521

Listener Status – lsnrctl status
11 17.05.2022
oracle@training19c:~/ [TVDNCDB] lsnrctl status
[…] Alias LISTENER
Version TNSLSNR for Linux: Version 19.0.0.0.0 - Production
Start Date 11-MAY-2019 11:01:30
Uptime 0 days 0 hr. 15 min. 47 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /u00/app/oracle/network/admin/listener.ora
Listener Log File /u00/app/oracle/diag/tnslsnr/training19c/listener/alert/log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=LISTENER)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=training19c.trivadistraining.com)(PORT=1521)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcps)(HOST=training19c.trivadistraining.com)(PORT=5500))(Security=(my_w
allet_directory=/u00/app/oracle/admin/TVDNCDB/xdb_wallet))(Presentation=HTTP)(Session=RAW))
Services Summary...
Service "TVDNCDB.trivadistraining.com" has 1 instance(s).
Instance "TVDNCDB", status READY, has 1 handler(s) for this service...
Service "TVDNCDBXDB.trivadistraining.com" has 1 instance(s).
Instance "TVDNCDB", status READY, has 1 handler(s) for this service...
The command completed successfully
Listener-logging should be
enabled when diagnosing
connection issues
Host+Port
Registered Services
Is the listener using the
correct listener.ora file?

12 17.05.2022
Check Network Infrastructure

Check Network Infrastructure (1)
13 17.05.2022
Check firewalls on client and server
Check network connectivity between client and server
– Ping (please note that ping uses the ICMP/IP protocol (not the TCP protocol)
– telnet from client to server on the Oracle Net port (if telnet is installed)
Name resolution from client to server
– Nslookup
– /etc/hosts
Do not forget to involve the system administrator and the network administrators

Check Network Infrastructure (2)
14 17.05.2022
Check for errors on network interface level
oracle@training19c:~/ [rdbms19000] ifconfig enp0s3
enp0s3: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.56.108 netmask 255.255.255.0 broadcast 192.168.56.255
inet6 fe80::3da9:2515:3ce2:2115 prefixlen 64 scopeid 0x20<link>
ether 08:00:27:b9:d8:65 txqueuelen 1000 (Ethernet)
RX packets 1962 bytes 169328 (165.3 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 1148 bytes 235620 (230.0 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

15 17.05.2022
Oracle Net Configuration

Oracle Net Configuration (1) – Listener does not start
16 17.05.2022
The listener does not start or uses the wrong port or hostname
– Check if the correct listener.ora is used
– Check value of $TNS_ADMIN
– Look for other listener.ora files on the database server, try to consolidate
– Multiple entries for the same listener in the listener.ora file?
Error "TNS-00512: Address already in use"
– Reason: Duplicate use of a TCP-Port
Error "NL-00303: syntax error in NV string"
– Syntax error in the listener.ora file
– In most cases "bracket errors"

Oracle Net Configuration (2) – Domain Name issues
17 17.05.2022
Oracle Net and Oracle Database can be configured using domains
Two areas:
– Instance parameter DB_DOMAIN => determines domain part of the default service name
which is registered with the listener
– Sqlnet.ora parameter NAMES.DEFAULT_DOMAIN => defines default domain for Oracle Net
connections
Inconsistencies can lead to " TNS-03505: Failed to resolve name"
Recommendations:
– Use consistent naming (DB_DOMAIN = NAMES.DEFAULT_DOMAIN)
– Use full qualified alias names in tnsnames.ora
– Use full qualified alias names on your clients (connection descriptors, JDBC URL etc.)

Oracle Net Configuration (3) – tnsping
18 17.05.2022
Tnsping helps you to find out
– Can the alias name be resolved?
– Which source is used for name resolution (LDAP, local tnsnames)?
– To which connection data is the alias resolved?
– Is there a listener running which is listening on the given hostname and port?
Tnsping does not check if there is a database instance running which provides the service
specified in the connection string
– You have to use e.g. SQL*Plus (or another tool which connects to the database) to
check this

19 17.05.2022
Sucessful tnsping:
oracle@training19c:/u00/app/oracle/network/admin/ [TVDNCDB] tnsping PDB01
TNS Ping Utility for Linux: Version 19.0.0.0.0 - Production on 11-MAY-2019 13:24:36
Copyright (c) 1997, 2019, Oracle. All rights reserved.
Used parameter files:
/u00/app/oracle/network/admin/sqlnet.ora
Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST =
training19c.trivadistraining.com)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED)
(SERVICE_NAME = PDB01.trivadistraining.com)))
OK (0 msec)
Location of the Oracle Net configuration files which are used
Naming method which is used (local tnsnames.ora)
Allowed methods and priorities are defined in sqlnet.ora
(NAMES.DIRECTORY_PATH)
Success

20 17.05.2022
Name can be resolved, but no listener is running on given port and host:
Name cannot be resolved
oracle@training19c:/u00/app/oracle/network/admin/ [TVDNCDB] tnsping PDB01
[..]
(SERVICE_NAME = PDB01.trivadistraining.com)))
TNS-12541: TNS:no listener Check if host and port are correct
oracle@training19c:/u00/app/oracle/network/admin/ [TVDNCDB] tnsping PDB01A
[..]
TNS-03505: Failed to resolve name
Check tnsnames.ora if entry exists

Oracle Net Configuration (6) – Database Connection
21 17.05.2022
Use SQL*Plus to check if the given database service is available:
oracle@training19c:/u00/app/oracle/network/trc/ [TVDNCDB] tnsping TVDNCDB
TNS Ping Utility for Linux: Version 19.0.0.0.0 - Production on 11-MAY-2019 15:08:23
[..]
(SERVICE_NAME = TVDNCDB.trivadistraining.com)))
OK (0 msec)
oracle@training19c:/u00/app/oracle/network/trc/ [rdbms19000] sqlplus
system/manager@TVDNCDB
SQL*Plus: Release 19.0.0.0.0 - Production on Sat May 11 15:05:43 2019
Version 19.3.0.0.0
ERROR:
ORA-12514: TNS:listener does not currently know of service requested in connect
descriptor
Listener is up, but there is no instance
registered which provides the service

Oracle Net Configuration (7) – Service Registration
22 17.05.2022
When a database instance is started, it registers itself with the listener (PMON process
(before 12c) or LREG process)
– Parameter LOCAL_LISTENER
As soon as the registration is complete, the listener is aware of the services which are
provided by the database instance
If you bounce the listener while the database is running, it can take up to 60 seconds
before the database "renews" the registration.
– This may lead to a (temporary) ORA-12514:
– You can enforce the registration:
ORA-12514: TNS:listener does not currently know of service requested in connect
descriptor
SQL> alter system register;
System altered.

Oracle Net Configuration (8) – Easy Connect
23 17.05.2022
If you want to rule out name resolution via LDAP or tnsnames, you can try Easy Connect
1. Allow Easy Connect via sqlnet.ora
2. Test the connection with Easy Connect (Host:Port/Service)
NAMES.DIRECTORY_PATH=(LDAP, TNSNAMES, EZCONNECT )
oracle@training19c:/u00/app/oracle/network/admin/ [TVDNCDB] tnsping
training19c.trivadistraining.com:1521/PDB01.trivadistraining.com
TNS Ping Utility for Linux: Version 19.0.0.0.0 - Production on 11-MAY-2019
13:56:58
Used EZCONNECT adapter to resolve the alias
Attempting to contact
(DESCRIPTION=(CONNECT_DATA=(SERVICE_NAME=PDB01.trivadistraining.com))(ADDRESS=
(PROTOCOL=tcp)(HOST=192.168.56.108)(PORT=1521)))
OK (0 msec)

Oracle Net Configuration (9) – Timeout
24 17.05.2022
With slow network connections, it can be helpful to check (and change) the timeout
parameters
sqlnet.ora
Use "0" to disable a parameter
Check your OS specific documentation for changing timeouts on OS level
SQLNET.INBOUND_CONNECT_TIMEOUT=n # server only, default 60 seconds,
# time allowed for authentication
SQLNET.OUTBOUND_CONNECT_TIMEOUT=n
SQLNET.RECV_TIMEOUT=n
SQLNET.SEND_TIMEOUT=n
TCP.CONNECT_TIMEOUT=n # default 60 seconds, time allowed to
# establish a TCP connection

Oracle Net Configuration (10) – tnsnames.ora in
general
25 17.05.2022
Recommendations
– All entries should be full qualified (especially when using a names.default_domain)
– Check for duplicate entries
– Check for "bracket errors"
– Errors in one entry may lead to name resolution failures in subsequent entries
==> add new entries at the end of the tnsnames.ora file
Example entry
PDB01.TRIVADISTRAINING.COM =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = training19c.trivadistraining.com)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = PDB01.trivadistraining.com)
) )
All names full qualified!

26 17.05.2022
Check Connectivity with the
Oracle Instant Client

Oracle Instant Client
27 17.05.2022
Lightweight Oracle Client
Requires no administrator or root privileges during installation
– Just unzip
Modular configuration, e.g. modules
– Required: "Basic Package " or "Basic Light Package"
– SQL*Plus Package
– JDBC Package
– ODBC Package
Download:
https://www.oracle.com/technetwork/database/database-technologies/instant-
client/downloads/index.html

Connection Tests using Instant Client
28 17.05.2022
In order to rule out configuration issues with your application, you can use instant client for
testing connections
– E.g. from your database server to your database server (using Oracle Net)
– From your application server to the database server
– Etc.
Procedure
1. Download and unzip all required packages
2. Set environment variables
3. Use your own Oracle Net configuration (tnsnames.ora etc.) for testing (=> set TNS_ADMIN)
4. Test the connection

29 17.05.2022
Check Oracle Client Version

Oracle Client – Server Certification (1)
30 17.05.2022
* 11.2.0.3 or 11.2.0.4 only
** was a supported combination, but is currently out of support
Special = limited support (special contract required)
Source: MOS note 207303.1
Client
Server
19c/18c/12.2 12.1 11.2 (*) 11.1 10.2
19c/18c /12.2 OK OK OK NO NO
12.1 OK OK OK NO** Special
11.2 (*) OK* OK OK NO** Special
11.1 NO NO** NO** NO** NO**
10.2 NO Special Special NO** Special

Oracle Client – Server Certification (2)
31 17.05.2022
Older clients may be able to connect, but there may be limited functionality or "strange
error messages" may occur
The minimum client version which can be used to connect to an Oracle 12.2 database (or
later) is Oracle 8i (8.1)
Especially when using Oracle Net encryption (free with every edition of the database)
older clients may no be able to connect
This may lead to connection issues after upgrading a database!
–  Check the client versions before upgrading a database!

Oracle Client – Find out the client versions
32 17.05.2022
select
sc.client_version,sc.client_driver,
s.machine,s.program,s.osuser,s.service_name,count(*)
from gv$session s,gv$session_connect_info sc
where sc.inst_id=s.inst_id
and sc.sid=s.sid and sc.serial#=s.serial#
and s.type<>'BACKGROUND'
group by sc.client_version,sc.client_driver,s.machine,s.program,s.osuser,s.service_name
order by sc.client_version,sc.client_driver,s.machine,s.program,s.osuser,s.service_name
/

33 17.05.2022
Check Password Versions

Check Password Versions
34 17.05.2022
Case-Sensitive Passwords
– Introduced with Oracle 10g
– Parameter SEC_CASE_SENSITIVE_LOGON as a workaround
– Parameter deprecated since Oracle 12c
Using SEC_CASE_SENSITIVE_LOGON will result in an ORA-32004 when starting the
database instance
– Solution: remove the parameter from the spfile
ORA-32004: obsolete or deprecated parameter(s) specified for %s instance
SQL> ALTER SYSTEM RESET sec_case_sensitive_logon scope=spfile sid='*';

Password versions (1)
35 17.05.2022
The algorithm for the password hashes was changed since Oracle 10c
– There may be different password versions (= password hashes) stored in the database
– A client needs a "compatible" password version in order to connect
SQL select password_versions from dba_users;
PASSWORD_VERSIONS
-----------------
10G 11G 12C
11G 12C
[..]

Password versions (2) – the problem
36 17.05.2022
The parameter SQLNET.ALLOWED_LOGON_VERSION_SERVER determines, which
password hashes are generated
– Default in Oracle 12.2: 12
–  Only 11G + 12C Hashes will be generated
–  10g-Clients cannot connect
ORA-1017: invalid username/password; logon denied

Password versions (3) – the solution
37 17.05.2022
1. Set SQLNET.ALLOWED_LOGON_VERSION_SERVER = 8
-  all password hashes will be generated
2. Make the database generate new password hashes (for users which are used by
Oracle 10g clients)
3. Users with Oracle 10g clients can connect 
SQL> ALTER USER <user> identified by <EXISTING_PASSWORD>;

38 17.05.2022
Oracle Net Logging & Tracing

Introduction
39 17.05.2022
Logging and tracing can provide more detailled information in order to diagnose
connectivity issues
Can be enabled on
– Listener Level
– Client Level
– Server Level
Tracing and logging can generate a huge number of large files,
do not forget to disable it after the issue has been solved

Listener.log (1)
40 17.05.2022
Enable listener logging
Listener.ora
Location of the listener.log in ADR:
Check the listener.log after each (failed) connection attempt for any error message
Listener.log can become huge => resize it before testing, e.g.
cp listener.log listener.log.backup; echo "" >listener.log
# enable or disable listener.log
LOGGING_LISTENER = ON
# Logging parameters, ignored if ADR is used
#LOG_DIRECTORY_LISTENER = /u00/app/oracle/network/log
#LOG_FILE_LISTENER = listener.log
$ORACLE_BASE/diag/tnslsnr/<hostname>/<listener_name>/trace

Listener.log (2) - Example
41 17.05.2022
11-DEC-2014 08:10:14 * (CONNECT_DATA=(CID=(PROGRAM=SQL
Developer)(HOST=__jdbc__)(USER=mbg))(SERVER=DEDICATED)(SERVICE_NAME=TVD12.
trivadistraining.com)) *
(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.56.1)(PORT=54163)) * establish *
TVD12.trivadistraining.com * 0
11-DEC-2014 08:10:59 *
(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=TVD12.trivadistraining.com)(
CID=(PROGRAM=C:Program?FilesDellToad?for?Oracle?12.6?TrialToad.exe)(HO
ST=LTMBG02)(USER=mbg))) *
(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.56.1)(PORT=54182)) * establish *
TVD12.trivadistraining.com * 0

Listener Tracing
42 17.05.2022
The listener uses the ADR infrastructure by default
For the classical version, the ADR must be deactivated in the LISTENER.ORA and the
listener must be restarted (DIAG_ADR_ENABLED_LISTENER=OFF)
Different trace levels are possible:
– OFF (0), USER (4), ADMIN (8), or SUPPORT (16)
DIAG_ADR_ENABLED_LISTENER = OFF
TRACE_LEVEL_LISTENER = 16
TRACE_DIRECTORY_LISTENER = /u00/app/oracle/network/trc
TRACE_FILE_LISTENER = listener.trc
TRACE_TIMESTAMP_LISTENER = TRUE

Server Logging
43 17.05.2022
Logging parameters
LOG_DIRECTORY_SERVER = /u00/app/oracle/network/log
LOG_FILE_SERVER = sqlnet_server.log

Server Tracing
44 17.05.2022
Since Oracle 11g trace and log files are stored by the client and the server in the
Automatic Diagnostic Directory (ADR)
For the classical version, the ADR must be deactivated in the SQLNET.ORA
The TRACE_*_SERVER parameters can then be set
TRACE_LEVEL_SERVER = 16
TRACE_DIRECTORY_SERVER = /u00/app/oracle/network/trc
TRACE_FILE_SERVER = sqlnet_server.trc
TRACE_TIMESTAMP_SERVER = TRUE
DIAG_ADR_ENABLED = OFF

Client Logging
45 17.05.2022
Logging Parameters
Example:
LOG_DIRECTORY_CLIENT = /u00/app/oracle/network/log
LOG_FILE_CLIENT = sqlnet_client.log
oracle@training19c:/u00/app/oracle/network/log/ [TVDNCDB] cat sqlnet_client.log
***********************************************************************
Fatal NI connect error 12514, connecting to:
(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=training19c.trivadistraining.com)(PORT=1521))(CONNECT_D
ATA=(SERVER=DEDICATED)(SERVICE_NAME=TVDNCDB.trivadistraining.com)(CID=(PROGRAM=sqlplus)(HOST=trai
ning19c.trivadistraining.com)(USER=oracle))))
VERSION INFORMATION:
TNS for Linux: Version 19.0.0.0.0 - Production
TCP/IP NT Protocol Adapter for Linux: Version 19.0.0.0.0 - Production
Version 19.3.0.0.0
Time: 11-MAY-2019 15:05:43
Tracing to file: /u00/app/oracle/network/trc/sqlnet_client_19495.trc
Tns error struct:
ns main err code: 12564
[..]

Client Tracing
46 17.05.2022
For the classical version, the ADR must be deactivated in the SQLNET.ORA
The TRACE_*_SERVER parameters can then be set
DIAG_ADR_ENABLED = OFF
TRACE_LEVEL_CLIENT = 16
TRACE_DIRECTORY_CLIENT = /u00/app/oracle/network/trc
TRACE_FILE_CLIENT = sqlnet_client.trc
TRACE_TIMESTAMP_CLIENT = TRUE

47 17.05.2022
Miscellaneous

Increase the Array Fetch Size
48 17.05.2022
Not in order to solve connection issues, but to improve performance
Increasing the array size will
– Reduce the number of fetches
– Reduce the number of packets to be transferred
Default value is 15
Changing the array fetch size is not always an option (think of 3rd party software)
SQLPLUS> SET ARRAYSIZE 49

Network Performance - Packet Size – MTU & SDU
49 17.05.2022
Both are performance related settings
MTU (Maximum Transmission Unit)
– Default: 1460 bytes
– Enlarging this value can help to reduce the number of packets sent over the network
– All network components must support higher values and have to be changed accordingly
SDU (Session data unit)
– Changing the "Session data unit" size can help to reduce Oracle Net related wait events
('SQL*Net message to client' and 'SQL*Net more data to client')
– Setting the default SDU size on client and server in sqlnet.ora
– Or use "(SDU_SIZE=8192)" in listener.ora and tnsnames.ora
DEFAULT_SDU_SIZE=8192

50 17.05.2022
More information

MOS-Notes (1)
51 17.05.2022
Oracle Net Diagnostics (Doc ID 834822.1)
SQL*Net & Oracle Net Services - Tracing and Logging at a Glance (Doc ID 219968.1)
How to Enable Oracle SQL*Net Client , Server , Listener , Kerberos and External procedure
Tracing from Net Manager (Doc ID 395525.1)
How To Limit Connections Generating Trace when Oracle Net Server Enabled (Doc ID 401134.1)
Intended Usage of the TNSPING Utility (Doc ID 787848.1)
How to Match Oracle Net Client and Server Trace Files (Doc ID 374116.1)
How to Perform the Equivalent of SQL*Net Client Tracing with Oracle JDBC Thin Driver (Doc ID
793415.1)
Shared Server (MTS) Diagnostics (Doc ID 1005259.6)
How to Diagnose Slow TNS Listener / Connection Performance (Doc ID 557416.1)
Listener Hanging - Information to Get For Resolving or Troubleshooting (Doc ID 230156.1)
Oracle Net (SQL*Net) Timeout Parameters (Doc ID 1560775.1)

MOS-Notes (2)
52 17.05.2022
Oracle Net Diagnostic Examples (Doc ID 1384945.1)
How to Reduce the TCP/IP Timeout for Oracle Net on Solaris (Doc ID 275189.1)
How to Configure Linux OS Ethernet TCP/IP Networking (Doc ID 132044.1)
Change MTU Size in Oracle Linux (Doc ID 2520148.1)
The relation between MTU (Maximum Transmission Unit) and SDU (Session Data Unit) (Doc ID
274483.1)
SQL*Net Packet Sizes (SDU & TDU Parameters) (Doc ID 44694.1)
Troubleshooting Waits for 'SQL*Net message to client' and 'SQL*Net more data to client' Events
from a Performance Perspective (Doc ID 1404526.1)
Oracle Net Performance Tuning (Doc ID 67983.1)
Starting With Oracle JDBC Drivers - Installation, Certification, and More! (Doc ID 401934.1)
SQL*Net & Oracle Net Services - Tracing and Logging at a Glance (Doc ID 219968.1)
RAC/SCAN: How to set SDU, Queuesize and Other Net Parameters for RAC Listeners (Doc ID
1292915.1)

Oracle Documentation & Other Links
53 17.05.2022
Documentation
– Net Services Administator's Guide - Part III Testing and Troubleshooting Oracle Net Services
https://docs.oracle.com/en/database/oracle/oracle-database/19/netag/part-III-test-and-
troubleshoot-oracle-net-services.html#GUID-E8B29E61-3236-486B-AB89-665215E86CFA
Other Links
– http://www.oracledbaplusbigdata.com/2018/01/27/sqlnet-ora-logging-and-tracing/

Questions and Answers
Markus Flechtner
Principal Consultant
Phone +49 211 5866 64725
Markus.Flechtner@Trivadis.com
@markusdba http://markusdba.de
Download the slides from https://www.slideshare.net/markusflechtner
Please don‘t forget the session evaluation – Thank you!
54

Oracle Database: Checklist Connection Issues

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