Cannot add specific Cloudflare IP range to Lightsail instance

You're encountering a limitation with Amazon Lightsail's firewall configuration. Lightsail has specific limits on firewall rules that might be affecting your ability to add the 104.24.0.0/14 CIDR range.

Each Lightsail instance has two firewalls - one for IPv4 and one for IPv6. The limit for adding source IP addresses is 30 at a time using the console, or up to 60 using the API, AWS CLI, or SDK. This limit applies separately to IPv4 and IPv6 rules.

There are a few possible reasons why the specific CIDR range isn't being added:

1. You may have reached the maximum number of firewall rules (60) for your instance.
2. The specific CIDR range might be too large or not properly formatted.
3. There could be an issue with how Lightsail processes this particular range.

To troubleshoot this issue:

• Try adding the range using the AWS CLI or SDK instead of the console, as this allows for up to 60 rules instead of 30.
• Consider breaking down the large CIDR range into smaller subnets if possible.
• Check if you've reached the quota for firewall rules in your account for that AWS Region.

If you continue to experience issues, you might need to contact AWS Support, as there could be an account-specific limitation or a technical issue with that particular CIDR range.
Sources
Lightsail Firewall Limit - Cloudfront | AWS re:Post
Lightsail IP/Port Quota Increase | AWS re:Post
PortInfo - Amazon Lightsail

I was able to verify that the range is, in fact, assigned to the instance by using the get-instance command in CloudShell. The issue appears to be that the Lightsail web dashboard is only displaying 14 of the 15 IPv4 ranges I've added.

When you create a new firewall rule with a CIDR range that overlaps with an existing rule's CIDR range, Lightsail automatically consolidates the overlapping ranges into a single, unified CIDR range.

For example, if you have an existing rule with CIDR range 172.16.10.0/24 (172.16.10.0 to 172.16.10.255) and add a new rule with 172.16.8.0/22 (172.16.8.0 to 172.16.11.255), the overlapping ranges will be merged into a single CIDR range (172.16.8.0 to 172.16.11.255).