Introduction:-
In this article, we are going to resolve ORA-12547 TNS lost lost contact error.
Error:-
ORA-12547: TNS:lost contact
$ sqlplus / as sysdba
SQL*Plus: Release 11.2.0.4.0 Production on Thu Mar 25 09:38:40 2021
Copyright (c) 1982, 2013, Oracle. All rights reserved.
ERROR:
ORA-12547: TNS:ost contact
Above error can occur for many reason. In my case oracle file system ownership issue. To fix this issue we have to check it as below and provide the appropriate permission.
oratest@test orahome]$ ls -ltr
total 3716
drwxrwxr-x 3 775 dba 4096 Jan 1 2017 usm
drwxrwxr-x 4 775 dba 4096 Jan 1 2017 uix
-rwxrwxr-x 1 775 dba 398 Jan 1 2017 root.sh
drwxrwxr-x 4 775 dba 4096 Jan 1 2017 relnotes
drwxrwxr-x 2 775 dba 4096 Jan 1 2017 utl
drwxrwxr-x 4 775 dba 4096 Jan 1 2017 suptools
drwxrwxr-x 7 775 dba 4096 Jan 1 2017 cfgtoollogs
drwxrwxr-x 26 775 dba 4096 Jan 1 2017 ow
Solution is to make sure file system for database home has setuid/suid set, database
binary($ORACLE_HOME/bin/oracle) has correct ownership and permission, and listener
owner is able to access database oracle binary (as listener owner, “ls -l
$ORACLE_HOME/bin/oracle” will tell)
If ownership and permission not correct make it change as below.
#chown -R oratest:dba /orahome
#chmod -R 775 /orahome
[oratest@test ~]$ cd $ORACLE_HOME
[oratest@test orahome]$ ls -ltr
total 3716
drwxrwxr-x 3 oratest dba 4096 Jan 1 2017 usm
drwxrwxr-x 4 oratest dba 4096 Jan 1 2017 uix
-rwxrwxr-x 1 oratest dba 398 Jan 1 2017 root.sh
drwxrwxr-x 4 oratest dba 4096 Jan 1 2017 relnotes
drwxrwxr-x 2 oratest dba 4096 Jan 1 2017 utl
drwxrwxr-x 4 oratest dba 4096 Jan 1 2017 suptools
drwxrwxr-x 7 oratest dba 4096 Jan 1 2017 cfgtoollogs
drwxrwxr-x 26 oratest dba 4096 Jan 1 2017 owb
drwxrwxr-x 3 oratest dba 4096 Jan 1 2017 wwg
drwxrwxr-x 3 oratest dba 4096 Jan 1 2017 ucp
drwxrwxr-x 13 oratest dba 4096 Jan 1 2017 ldap
drwxrwxr-x 4 oratest dba 4096 Jan 1 2017 deinstall
drwxrwxr-x 3 oratest dba 4096 Jan 1 2017 slax
drwxrwxr-x 8 oratest dba 4096 Jan 1 2017 xdk
drwxrwxr-x 13 oratest dba 4096 Jan 1 2017 sqldeveloper
drwxrwxr-x 5 oratest dba 4096 Jan 1 2017 olap
drwxrwxr-x 8 oratest dba 4096 Jan 1 2017 precomp
drwxrwxr-x 3 oratest dba 4096 Jan 1 2017 has
drwxrwxr-x 4 oratest dba 4096 Jan 1 2017 clone
drwxrwxr-x 10 oratest dba 4096 Jan 1 2017 ord
drwxrwxr-x 4 oratest dba 4096 Jan 1 2017 sqlj
drwxrwxr-x 2 oratest dba 4096 Jan 1 2017 mesg
drwxrwxr-x 6 oratest dba 4096 Jan 1 2017 css
drwxrwxr-x 2 oratest dba 4096 Jan 1 2017 timingframework
drwxrwxr-x 8 oratest dba 4096 Jan 1 2017 apex
drwxrwxr-x 15 oratest dba 4096 Jan 1 2017 sysman
drwxrwxr-x 8 oratest dba 4096 Jan 1 2017 oui
drwxrwxr-x 3 oratest dba 4096 Jan 1 2017 demo
drwxrwxr-x 8 oratest dba 4096 Jan 1 2017 sqlplus
drwxrwxr-x 3 oratest dba 4096 Jan 1 2017 jpub
drwxrwxr-x 4 oratest dba 4096 Jan 1 2017 jdev
drwxrwxr-x 2 oratest dba 4096 Jan 1 2017 instantclient
drwxrwxr-x 13 oratest dba 4096 Jan 1 2017 rdbms
drwxrwxr-x 8 oratest dba 4096 Jan 1 2017 OPatch_11.2.0.3.4
drwxrwxr-x 10 oratest dba 4096 Jan 1 2017 rda
drwxrwxr-x 9 oratest dba 4096 Jan 1 2017 srvm
drwxrwxr-x 4 oratest dba 4096 Jan 1 2017 owm
drwxrwxr-x 14 oratest dba 4096 Jan 1 2017 inventory
drwxrwxr-x 8 oratest dba 4096 Jan 1 2017 nls
drwxrwxr-x 3 oratest dba 4096 Jan 1 2017 patch
If ownership and permission of $ORACLE_HOME/bin/oracle is not correct.
Change permissions as below:
cd $ORACLE_HOME/bin/
ls -ltr oracle
-rwsr-s–x 1 oratest dba 136803483 Mar 16 20:32 oracle
chmod 6751 oracle
If you are interested to more ORA-error click here.