How to further diagnose listener-thread: err = -25580: oserr = 1

Resolving The Problem

online.log shows following message at a regular interval
listener-thread: err = -25580: oserr = 1: errstr = : System error occurred in network function. System error = 1.
listener-thread: err = -25580: oserr = 1: errstr = : System error occurred in network
function. System error = 1.

Turn on the following xtrace.

xtrace size 50000                             
xtrace heavy -c XTF_IPTRACE -f XTF_SYSCALLS      
xtrace on

After error messages are seem in the online.log for few seconds turn off xtrace
xtrace off                                      
xtrace fview > xtrace.out   

Review xtrace.out for IP address which might be pinging/checking the port the IDS server is listening on.

The above messages indicate we accepted the client connections but received 0 bytes and then client closed the connection.

Customer could use following query to monitor instance instead of using port monitoring software

select * from sysmaster:sysdual

which outputs:

dummy

X

But if above is not an option customer could ignore those error messages.