Postgres dying after many failed logins

Hello all-

I have a postgres instance running on an AWS ec2 machine (not RDS ).  It is receiving many hits from the hacker address
209.141.53.139.   Because this address has been implicated in hacker attempts previously, I have the pg_hba.conf set to
explicitlyreject this address ( so I can see how many times it hits).  https://www.abuseipdb.com/check/209.141.53.139
 

Note there are other restrictions on which addresses are allowed to connect, and we have non-default passwords setup on
thisdb.  
 

I'm finding that after postgres is hit by and rejects many connections, it dies.  I haven't been able to find any
documentationthat explains failed connections causing the server to die but that is what I'm seeing.  In the log file
thereare multiple of these messages:
 

2021-11-04 15:14:46.537 UTC [1513486] postgres@postgres FATAL:  pg_hba.conf rejects connection for host
"209.141.53.139",user "postgres", database "postgres", SSL on
 
2021-11-04 15:14:46.709 UTC [1513488] postgres@postgres FATAL:  pg_hba.conf rejects connection for host
"209.141.53.139",user "postgres", database "postgres", SSL off
 
2021-11-04 15:14:48.566 UTC [1513494] postgres@postgres FATAL:  pg_hba.conf rejects connection for host
"209.141.53.139",user "postgres", database "postgres", SSL on
 
2021-11-04 15:14:48.761 UTC [1513505] postgres@postgres FATAL:  pg_hba.conf rejects connection for host
"209.141.53.139",user "postgres", database "postgres", SSL off
 
 ....
2021-11-05 11:13:49.519 UTC [1834715] postgres@postgres FATAL:  pg_hba.conf rejects connection for host
"209.141.53.139",user "postgres", database "postgres", SSL on
 
2021-11-05 11:13:49.702 UTC [1834718] postgres@postgres FATAL:  pg_hba.conf rejects connection for host
"209.141.53.139",user "postgres", database "postgres", SSL off
 
2021-11-05 14:35:09.197 UTC [1451469] LOG:  received smart shutdown request
2021-11-05 14:35:09.222 UTC [1451660] postgres@breedbase FATAL:  terminating connection due to administrator command
2021-11-05 14:35:09.222 UTC [1451662] postgres@breedbase FATAL:  terminating connection due to administrator command

And after the time span seen here, the log shows a smart shutdown request message shown above.  All connections are
terminatedand the system is shut down.
 


My question:  Is this expected behavior, ie that the server will shutdown after hours of failed attempts?  Is there
anythingI can do to prevent this, or further secure the database?  The hackers are unsuccessful due to the rejected
connections,but it is a problem that the database server is continually shut down.
 

Thanks - Lynn