Is "lsnrctl reload" enough after updating sqlnet.ora?

Question:After implementing TCP.VALIDNODE_CHECKING, is simple "lsnrctl reload" good enough to make the changes effective?

Answer:It depends. if sqlnet.ora is not in use for current running listener, then you must stop the listener and start the listener again.
If sqlnet.ora already being utilized, then lsnrctl reload is a faster way. Current running connections are not affected, dynamic service registration completed very fast.

Very importantly, the IP address (or hostname) for the database server itself must be included in the TCP.INVITED_NODES.

[oracle@vmxdb02 admin]$ cat sqlnet.ora 
# sqlnet.ora Network Configuration File: /u01/app/oracle/oracle/product/10.2.0/db_1/network/admin/sqlnet.ora
# Generated by Oracle configuration tools.

NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)

TCP.VALIDNODE_CHECKING=yes
#TCP.INVITED_NODES=(192.168.1.22,192.168.1.21)
TCP.INVITED_NODES=(192.168.1.22)