Step 1. Choose your RDS database from the list of instances:

Step 2. Scroll to the "Details" section then find the "Security groups" and click on the active security group link. This will directly redirect you to the security group you need to whitelist the IP address at.

Step 3. Make sure the security group that belongs to your RDS database is selected/highlighted. If you are not sure which one it is, you can match them by the VPC ID (in this case it's the one ending in 0bc0) or the GROUP IP (ending in 6cbf).

Step 4. Click on "Inbound" at the bottom (you can also right click the highlighted item and click "Edit inbound rules"). Then click "Edit".

Step 5. In this last step you will just need to select the port to whitelist or grant access to. If you are using the default MySQL port then selecting the "MYSQL/Aurora" option works. If you are using a custom port for your database, then under the "Type" dropdown select "Custom TCP Rule" and type the port number in the "Port Range" field.

Step 6. Under the "Source" we finally add the IP address or IP range we need to whitelist. Note: The IP addresses you enter here must be not he range format, which means that you need to append /32 to the end of your IP address.

Example: to whitelist 8.8.8.8 you need to enter 8.8.8.8/32 in the source field.

Don't forget to click "Save" then you are done ✅