Cannot connect to Oracle XE 11g2 - oracle

Question

This has been driving me crazy for two days. I recently installed Oracle Express Edition 11g2 on my localhost (Windows 7 Enterprise). I can start the database and the listener, but I am unable to connect.
When I try connecting from SQL Developer with the following parameters:
Username: SYSTEM
Password: ***********
Hostname: localhost
Port: 1521
Service name: XE
I get the following error: An error was encountered... IO Error: The Network Adapter could not establish the connection. Vendor code 17002
Which apparently is SQL Developer speak for ORA-12541: TNS no listener.
When i try to connect from an SQL Command Line:
SQL> connect
Enter user-name: system
Enter password:
ERROR:
ORA-12638: Credential retrieval failed
My ORACLE_HOME is set to C:\oraclexe\app\oracle\product\11.2.0\server.
C:\oraclexe\app\oracle\product\11.2.0\server\network\ADMIN\tnsnames.ora:
XE =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = LOCALHOST)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = XE)
)
)
EXTPROC_CONNECTION_DATA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
)
(CONNECT_DATA =
(SID = PLSExtProc)
(PRESENTATION = RO)
)
)
ORACLR_CONNECTION_DATA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
)
(CONNECT_DATA =
(SID = CLRExtProc)
(PRESENTATION = RO)
)
)
#bohort =
# (DESCRIPTION=
# (ADDRESS=(PROTOCOL=tcp)(HOST=LOCALHOST)(PORT=1521))
# (CONNECT_DATA=(SID=bohort))
# (HS=OK)
# )
-
C:\oraclexe\app\oracle\product\11.2.0\server\network\ADMIN\listener.ora:
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = C:\oraclexe\app\oracle\product\11.2.0\server)
(PROGRAM = extproc)
)
(SID_DESC =
(SID_NAME = CLRExtProc)
(ORACLE_HOME = C:\oraclexe\app\oracle\product\11.2.0\server)
(PROGRAM = extproc)
)
# (SID_DESC=
# (SID_NAME=bohort)
# (ORACLE_HOME= C:\oraclexe\app\oracle\product\11.2.0\server)
# (PROGRAM=dg4odbc)
# )
)
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
)
)
DEFAULT_SERVICE_LISTENER = (XE)
-
C:\oraclexe\app\oracle\product\11.2.0\server\network\ADMIN\sqlnet.ora:
# This file is actually generated by netca. But if customers choose to
# install "Software Only", this file wont exist and without the native
# authentication, they will not be able to connect to the database on NT.
SQLNET.AUTHENTICATION_SERVICES = (NTS)
Starting the listener seems to work fine:
C:\Users\<Username>>lsnrctl start
LSNRCTL for 64-bit Windows: Version 11.2.0.2.0 - Production on 04-F╔VR.-2015 10:
45:27
Copyright (c) 1991, 2014, Oracle. All rights reserved.
Starting tnslsnr: please wait...
TNSLSNR for 64-bit Windows: Version 11.2.0.2.0 - Production
System parameter file is C:\oraclexe\app\oracle\product\11.2.0\server\network\ad
min\listener.ora
Log messages written to C:\oraclexe\app\oracle\diag\tnslsnr\<Username>\listener\a
lert\log.xml
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(PIPENAME=\\.\pipe\EXTPROC1ipc
)))
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=127.0.0.1)(PORT=1521)))
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1)))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for 64-bit Windows: Version 11.2.0.2.0 - Produ
ction
Start Date 04-F╔VR.-2015 10:45:32
Uptime 0 days 0 hr. 0 min. 5 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Default Service XE
Listener Parameter File C:\oraclexe\app\oracle\product\11.2.0\server\network\a
dmin\listener.ora
Listener Log File C:\oraclexe\app\oracle\diag\tnslsnr\<Username>\listener
\alert\log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(PIPENAME=\\.\pipe\EXTPROC1ipc)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=127.0.0.1)(PORT=1521)))
Services Summary...
Service "CLRExtProc" has 1 instance(s).
Instance "CLRExtProc", status UNKNOWN, has 1 handler(s) for this service...
Service "PLSExtProc" has 1 instance(s).
Instance "PLSExtProc", status UNKNOWN, has 1 handler(s) for this service...
The command completed successfully
I am sure the answer is out there somewhere but two days of googling have not led to a solution ...

Answer 1

Please use IP Address 127.0.0.1 instead of LOCALHOST in the listener and TNSNAMES file.
Restart the listener and try to connect again.