When I try to install something via yum (e.g., yum install java), I get the following:

```
Could not contact CDS load balancer rhui2-cds01.us-west-2.aws.ce.redhat.com, trying others.

Could not contact any CDS load balancers: rhui2-cds01.us-west-2.aws.ce.redhat.com, rhui2-cds02.us-west-2.aws.ce.redhat.com.

```

Earlier today I installed various yum packages. This evening I tried several, but none worked.

This link explains that certain firewall rules need to be made:
<https://access.redhat.com/solutions/11214>

I don't have an explanation why all Yum install commands were working earlier today. Several different ones later stopped working. Here is the solution: via the AWS console, I opened all traffic over port 443 (inbound and outbound traffic). 

This isn't an ideal solution or a permanent solution. The security groups in the AWS console only permit filtering based on IP addresses and IP address ranges. DNS names aren't part of the filtering.

Using AWS, how can I open port 443 and port 80 to specific DNS names?