Database server IP changes

1) Changes ip in tnsnames.ora file.

2)  C:\Users\Administrator>sqlplus as sysdba

SQL*Plus: Release 11.2.0.1.0 Production on Tue Feb 20 13:49:54 2018

Copyright (c) 1982, 2010, Oracle.  All rights reserved.

Connected to an idle instance.

SQL> startup
ORACLE instance started.

Total System Global Area 1670221824 bytes
Fixed Size                  2176328 bytes
Variable Size            1275071160 bytes
Database Buffers          385875968 bytes
Redo Buffers                7098368 bytes
Database mounted.
ORA-03113: end-of-file on communication channel
Process ID: 3728
Session ID: 5 Serial number: 5


SQL> startup mount
ORA-24324: service handle not initialized
ORA-01041: internal error. hostdef extension doesn't exist
SQL> exit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64
bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

C:\Users\Administrator>sqlplus / as sysdba

SQL*Plus: Release 11.2.0.1.0 Production on Tue Feb 20 13:52:26 2018

Copyright (c) 1982, 2010, Oracle.  All rights reserved.

Connected to an idle instance.

SQL> startup mount
ORACLE instance started.

Total System Global Area 1670221824 bytes
Fixed Size                  2176328 bytes
Variable Size            1275071160 bytes
Database Buffers          385875968 bytes
Redo Buffers                7098368 bytes
Database mounted.
SQL> alter database clear unarchived logfile group 1;

Database altered.

SQL> alter database clear unarchived logfile group 2;

Database altered.

SQL> alter database clear unarchived logfile group 3;

Database altered.

SQL> alter database open;
Database altered.

SQL>