Hi,
Sometimes You can get “TNS-00517: Lost contact ” error.
Details of error are as follows.
TNS-00517: Lost contact
Cause: Partner has unexpectedly gone away.
Action: Investigate partner application for abnormal termination.
When you got this error, check your /etc/hosts file, if the following entry don’t exist in the /etc/hosts file,
127.0.0.1 localhost.localdomain localhost
then add it and try to start Listener again.
[oracle@msdbadm01 ~]$ lsnrctl start LISTENER
Check listener status as follows, it is listening the Database and its service as follows.
[oracle@msdbadm01 ~]$ lsnrctl status LSNRCTL for Linux: Version 18.0.0.0.0 - Production on 28-APR-2020 15:44:29 Copyright (c) 1991, 2019, Oracle. All rights reserved. Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521)) STATUS of the LISTENER ------------------------ Alias LISTENER Version TNSLSNR for Linux: Version 18.0.0.0.0 - Production Start Date 25-MAR-2020 20:34:20 Uptime 33 days 19 hr. 10 min. 8 sec Trace Level off Security ON: Local OS Authentication SNMP OFF Listener Parameter File /u01/grid/network/admin/listener.ora Listener Log File /u01/app/grid/diag/tnslsnr/vfxidb01/listener/alert/log.xml Listening Endpoints Summary... (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=LISTENER))) (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.63.34)(PORT=1521))) Services Summary... Service "+APX" has 1 instance(s). Instance "+APX1", status READY, has 1 handler(s) for this service... Service "+ASM" has 1 instance(s). Instance "+ASM1", status READY, has 1 handler(s) for this service... Service "+ASM_DATA" has 1 instance(s). Instance "+ASM1", status READY, has 1 handler(s) for this service... Service "+ASM_RECO" has 1 instance(s). Instance "+ASM1", status READY, has 1 handler(s) for this service... Service "MSDB" has 1 instance(s). Instance "MSDB1", status READY, has 1 handler(s) for this service... Service "MSDBXDB" has 1 instance(s). Instance "MSDB1", status READY, has 1 handler(s) for this service... [oracle@msdbadm01 ~]$
Do you want to learn more details about RMAN, then read the following articles.
https://ittutorial.org/rman-backup-restore-and-recovery-tutorials-for-beginners-in-the-oracle-database/