Receive "undefined symbol: nlgh" or "symbol nlgh: referenced symbol not found" when running lsnrctl utility

(Doc ID 944886.1)

Last updated on NOVEMBER 17, 2015

Applies to:

Oracle Net Services - Version to [Release 11.1 to 11.2]
Generic UNIX
Generic Linux


1. After a new install or a change to an existing install (such as CPU upgrade), which may have seemed to go without problems, you might get the following error when trying to run the lsnrctl utility to start your listener (following based on a listener called LISTENER_DB1 located and running out of the ASM Home):

> ./lsnrctl status LISTENER_DB1 [Enter]

> ./lsnrctl: symbol lookup error: ./lsnrctl: undefined symbol: nlgh

2. Also, the following error has been reported on a few occasions, especially with 11.2 installations:

> lsnrctl [Enter]

> lsnrctl: fatal: relocation error: file /opt/vendor/oracle/product/ symbol nlgh: referenced symbol not found

* The "file" value may differ depending on the $ORACLE_HOME setting.


One of the following may have been done:
- New installation
- OS or Oracle Patch / Patchset upgrade
- Other OS change


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