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Can't resolve tns 12541 error [message #481167] Mon, 01 November 2010 06:28 Go to next message
aviana
Messages: 106
Registered: July 2007
Senior Member
Hi
My database link to the remote database used to work fine until the company VPN was updated for some security reasons.
Now When I try to connect using the DBlink now, error comes up:
TNS 12541 no listener.
Checked the actual listener on the remote database(destination) and it is up and running fine.
I am able to ping their machine.
ping <remote host> -works fine
tnsping<remte host> -fails
it comes back with error
TNS 12541: no listener
Nothing has been changed on both databases. The destination database can connect to our database without any issues(they can tnsping and use the dblinks to our database).
LISTENER ENTRY:
LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
      (ADDRESS = (PROTOCOL = TCP)(HOST = <OUR HOSTNAME>)(PORT = 1521))
    )
  )

tnsentry for the remote database:
REMOTE.WORLD =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = <IPADDRESS>)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = <SERVICENAME>)
    )
  )



SQLNET.ORA FILE
SQLNET.AUTHENTICATION_SERVICES= (NTS)
NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)

None of the above should be the cause because there was no change been made on any of these.
Looking for guideline how to troubleshoot more.
Please help in resolving this.
Re: Can't resolve tns 12541 error [message #481216 is a reply to message #481167] Mon, 01 November 2010 20:22 Go to previous messageGo to next message
BlackSwan
Messages: 26766
Registered: January 2009
Location: SoCal
Senior Member
If, as you stated that nothing changed with the Oracle environment, known changes were made to network/VPN,
I suggest you request assistance from the Network Administrator to determine what broke SQL*Net access.
Re: Can't resolve tns 12541 error [message #481346 is a reply to message #481216] Tue, 02 November 2010 12:32 Go to previous messageGo to next message
aviana
Messages: 106
Registered: July 2007
Senior Member
Thanks BlackSwan for the suggestion.
Talked to network people and security guys (for the firewall settings) and they say nothing is changed as well..
No findings yet until now from their side.
I put a tracefile on sqlnet.ora and did a tnsping to the remote server.
This file contents are below:Can somebody give some clues based on this?

TNS Ping Utility for 32-bit Windows: Version 11.1.0.7.0 - Production on 02-NOV-2010 17:31:16

Copyright (c) 1997, 2008, Oracle.  All rights reserved.

--- TRACE CONFIGURATION INFORMATION FOLLOWS ---
New trace stream is f:\oracle11g\home\network\trace\tnsping.trc
New trace level is 4
--- TRACE CONFIGURATION INFORMATION ENDS ---
--- PARAMETER SOURCE INFORMATION FOLLOWS ---
Attempted load of system pfile source f:\oracle11g\home\network\admin\sqlnet.ora
Parameter source loaded successfully

 -> PARAMETER TABLE LOAD RESULTS FOLLOW <-
Successful parameter table load
 -> PARAMETER TABLE HAS THE FOLLOWING CONTENTS <-
  TNSPING.TRACE_LEVEL = user
  NAMES.DIRECTORY_PATH = (TNSNAMES, EZCONNECT)
  SQLNET.AUTHENTICATION_SERVICES = (NTS)
--- PARAMETER SOURCE INFORMATION ENDS ---
--- LOG CONFIGURATION INFORMATION FOLLOWS ---
Log stream will be "standard output"
Log stream validation not requested
--- LOG CONFIGURATION INFORMATION ENDS ---

nnftmlf_make_local_addrfile: construction of local names file failed
nnftmlf_make_system_addrfile: system names file is f:\oracle11g\home\network\admin\tnsnames.ora
nscall: connecting...
nsc2addr: (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=172.16.1.71)(PORT=1521))(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=orc1)))
nttbnd2addr: using host IP address: 172.16.1.71
nsopen: opening transport...
nttcni: Tcp conn timeout = 0 (ms)
nttcni: trying to connect to socket 1716.
ntt2err: soc 1716 error - operation=1, ntresnt[0]=511, ntresnt[1]=61, ntresnt[2]=0
nserror: nsres: id=0, op=65, ns=12541, ns2=12560; nt[0]=511, nt[1]=61, nt[2]=0; ora[0]=0, ora[1]=0, ora[2]=0
nsopen: unable to open transport
nscall: connecting...

thanks a lot
Re: Can't resolve tns 12541 error [message #481347 is a reply to message #481346] Tue, 02 November 2010 12:37 Go to previous message
BlackSwan
Messages: 26766
Registered: January 2009
Location: SoCal
Senior Member
nttcni: trying to connect to socket 1716.
ntt2err: soc 1716 error - operation=1, ntresnt[0]=511, ntresnt[1]=61, ntresnt[2]=0
nserror: nsres: id=0, op=65, ns=12541, ns2=12560; nt[0]=511, nt[1]=61, nt[2]=0; ora[0]=0, ora[1]=0, ora[2]=0
nsopen: unable to open transport

Appears to me that network is not cooperating.
Since tnsping fails, it says to me root cause is external to Oracle.
Oracle is victim & not the culprit.
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