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Don Burleson Blog 







ORA-28575 Tips

Oracle Database Tips by Donald BurlesonApril 7, 2015

Question:  I tried to use external C procedure from the database and I aam getting the ORA-28575 error at run time:

28575. 00000 - "unable to open RPC connection to external procedure agent"

How to I fox the ORA-28575 error?.

Answer:  First, if the C program contains Oracle SQL, you must use the Pro*C precompiler as a compile step:

First, use the oerr utility to look-up the 28575. 00000 - "unable to open RPC connection to external procedure agent" error:

ORA-28575: unable to open RPC connection to external procedure agent

Cause: Initialization of a network connection to the extproc agent did not succeed.

This problem can be caused by network problems, incorrect listener configuration, or incorrect transfer code.

Action: Check listener configuration in LISTENER.ORA and TNSNAMES.ORA, or check Oracle Names Server.

Start by ensuring that your EXTPROC is present in tnsnames.ora and listener.ora:

Here are how to add extproc entries to tnsnames.ora and listener.ora:


Add this line in $ORACLE_HOME/network/admin/tnsnames.ora




Add/edit this line in $ORACLE_HOME/network/admin/listener.ora




(SID_DESC=(SID_NAME=extproc)(ORACLE_HOME=/myhome/orac le)


After verifying the EXTPROC entries, tart with these obvious diagnostic steps for the ORA-28575 error:

1 - Ensure that your extproc entry exists in your tnsnames.ora and listener.ora.

2 - Then check the Oracle doc "Network Configuration Guide" for your OS platform for details on creating an entry for extproc.

3 - If you add extproc to your listener.ora, bounce the listener

If that does not fix your ORA-28575 error, try these steps to troubleshoot your network connectivity:

1 - try changing your IP Address to your Host name

2 - See if the listener is running with "lsntctl stat"

3 - Check with "ping" using the IP address ("ping" )

4 - Check with "ping" using DNS name (e.g. "tnsping uranus")

5 - Try telnet to the IP on port 1521 (telnet 1521)

6 - Check with "tnsping" using TNS service name (

7 - Invoke SQL*Plus from the OS command line "sqlplus fred@flintstone". If this fails, check to ensure that your listener is the flintstone service defined.

8 - Sign-on to SQL*Plus and connect with the TNS name ("connect fred/flintstome@service_name"

9 - Within SQL*Plus, try a select from table@remote_db_link


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