AWS RDS Unknown MySQL Server Host error causing trouble? Read on to resolve this issue. 

At Bobcares, we offer solutions for every query, big and small, as a part of our AWS Support Services.

Let’s take a look at how our AWS Support Team is ready to help customers resolve Unknown MySQL Server Host error.

What is AWS RDS: “Unknown MySQL Server Host” error?

Every now and then, our customers come across the “Unknown MySQL Server Host” error in AWS RDS. According to our MySQL Server experts, this error is due to internal name servers in AWS. Rather than return an IP address, they time out or return an empty answer resulting in the error. In other words. The “Unknown MySQL Server Host” error message pops up due to hostup lookup fails.

Fortunately, our experts have come up with a solution to resolve Unknown MySQL Server Host” error.

How to resolve Unknown MySQL Server Host error

First, use the PHP function gethostbyname() to access the IP address from the DNS name as seen here:

<?php $ip_addr = gethostbyname('abcdefgh.stuvwxyz.ap-southeast-1.rds.amazonaws.com'); 
   $con = mysqli_connect($ip_addr,"my_user","my_password","my_db");?>

Alternatively, here is another solution to the Unknown MySQL Server Host error:

1. To begin with, verify the RDS instance’s endpoint is correct. If it is incorrect, it may be due to one of the following reasons:
   • Invalid endpoint format
   • Manually releasing a public endpoint
   • Endpoint exceeds maximum length</li
2. If the endpoint is correct, we have to try changing the DNS server IP addresses as seen here:
   • If we connect to the RDS instance through the classic network change the DNS server IP addresses to 10.143.22.118 and 10.143.22.116.
   • In case we connect to the RDS instance through an internal network by changing the DNS server IP addresses to 100.100.2.138 and 100.100.2.136.
   • If we connect to the RDS instance through the Internet, change the DNS server IP addresses to 223.6.6.6 and 223.5.5.5.

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Conclusion

In a nutshell, our skilled AWS Support Engineers at Bobcares demonstrated how to resolve the RDS Unknown MySQL Server Host error.