Issues with Callback Routing from Specific IPs on AWS Lightsail Instance

Based on the information provided, it appears that you're facing a complex connectivity issue with your Amazon Lightsail instance. Let's address your concerns and provide some insights:

1. Internal AWS routing issues: It's unlikely that there's an internal AWS routing problem specifically affecting these IP addresses. AWS's global network is designed to handle traffic efficiently across regions and IP ranges.

2. Additional steps and configurations:

   • Double-check your firewall rules: Ensure that you have separate rules for both IPv4 and IPv6 if necessary. Lightsail instances have two separate firewalls for each protocol.
   • Verify port configurations: Confirm that the specific ports required for the callbacks (likely 80 for HTTP and 443 for HTTPS) are open in your firewall rules for the specified IP addresses.
   • Check instance security groups: If you're using additional security groups, make sure they're not blocking the incoming traffic.

3. Regional or infrastructure-level restrictions:

   • There are no known regional restrictions that would specifically block these IP addresses.
   • However, it's worth noting that firewall rules in Lightsail only affect traffic coming through the public IP address of your instance. Traffic through the private IP address is not affected by these rules.

Additional troubleshooting steps:

1. Review your application logs to see if the requests are reaching your application at all.
2. Use a network monitoring tool on your instance to capture incoming traffic and verify if the requests are being received at the network level.
3. Consider temporarily allowing all inbound traffic (not recommended for production) to isolate whether it's a firewall issue or an application-level problem.
4. Check if there are any NAT gateways or load balancers in front of your instance that might be interfering with the traffic.

If the issue persists after these steps, it would be advisable to contact AWS Support for a more in-depth investigation, as they can provide specific insights into your account and infrastructure setup.
Sources
Control instance traffic with firewalls in Lightsail - Amazon Lightsail
View and manage IP addresses for Lightsail resources - Amazon Lightsail
Troubleshoot common Lightsail resource issues - Amazon Lightsail