title: Can't connect to RDS instance from EC2 instance
body: <p>From EC2 instance i-78a8df00, I'm trying to connect to RDS instance mysql.************.us-east-1.rds.amazonaws.com. They are both in the U.S. East region. I added the security group of EC2 instance (sg-********) to the RDS security group, but that didn't help. It appears to be a firewall/DNS issue as it is timing out when running this command:</p>
  
  <pre><code>ubuntu@ip-10-195-189-237:~$ mysql -h mysql.************.us-east-1.rds.amazonaws.com
  </code></pre>
  
  <blockquote>
    <p>ERROR 2003 (HY000): Can't connect to MySQL server on 'mysql.************.us-east-1.rds.amazonaws.com' (110)</p>
  </blockquote>
  
  <p>I can connect to RDS instance fine from my local machine using the same line as above. I tried various forum solutions but those don't help.</p>