First of all, a firewall is a system designed to prevent unauthorised access to or from a private network. We don’t use fixed IP addresses as they will be dynamically assigned by our infrastructure provider. We don't perform any IP address blocking or filtering.
If you're experiencing some issues and system is blocking you the access to some Lightful sites/features, it may worth checking with your IT department and confirm port 80 and 443 are open.
Let me know if you need further assistance dropping me an email via firstname.lastname@example.org.