ORA-12541: TNS:no listener using EXPDP I need to export an Oracle 11g database to an Oracle 10g instance.  I have the command, which I believe is correct:

expdp user/pass@192.168.10.8 full=Y VERSION=10.2 directory=m_dump 
    dumpfile=DB10G.dmp logfile=expdpDB10G.log


When I run this I always get this error:

UDE-12541: operation generated ORACLE error 12541
ORA-12541: TNS:no listener


I can connect to the server with SQLDeveloper, the 'no listener' error only occurs with this command.
You're not supplying a correct connection string. If you're using ezconnect, you need to pass the connection string in the format: //host:port/service-name

The expdp command-line should be:

expdp user/pass@//host:port/service-name full=Y VERSION=10.2 directory=m_dump dumpfile=DB10G.dmp logfile=expdpDB10G.log


So, something like:

expdp user/pass@//192.168.10.8:1521:DB10G full=Y VERSION=10.2 directory=m_dump dumpfile=DB10G.dmp logfile=expdpDB10G.log


If your local machine is not configured to use ezconnect, you need to specify the TNS name for the database, like so:

expdp user/pass@DB10G full=Y VERSION=10.2 directory=m_dump dumpfile=DB10G.dmp logfile=expdpDB10G.log


... and ensure there's a relevant TNS entry in your tnsnames.ora file.