I have an Amazon RDS Postgres instance running. I can see the data from my local machine (whitelist office IP) and our web app can connect (running on EC2 instance).
On that EC2 instance, these things happen:
[ec2-user@ip ~]$ nc -zv mydb.us-east-1.rds.amazonaws.com 5432 Connection to mydb.us-east-1.rds.amazonaws.com 5432 port [tcp/postgres] succeeded! [ec2-user@ip ~]$ psql postgres -h mydb.us-east-1.rds.amazonaws.com -U userguy Password for user userguy: psql (9.5.4, server 9.6.1) WARNING: psql major version 9.5, server major version 9.6. Some psql features might not work. SSL connection (protocol: TLSv1.2, cipher: ECDHE-RSA-AES256-GCM-SHA384, bits: 256, compression: off) Type "help" for help. postgres=> \q [ec2-user@ip myjars]$ java -jar MyJar.jar param1 Connecting to jdbc:postgresql://mydb.us-east-1.rds.amazonaws.com:5432/postgres org.postgresql.util.PSQLException: Connection refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.
I know this EC2 instance can connect to the DB. The
nc command works and the
psql command works. We have a Glassfish application server that connects as well.
Same parameters are in this JAR file and it does not work! Any thoughts? Any ideas to diagnose? (as I type this, I feel it will be some file version or mistyped value in the JAR file, since everything else is working)