Hi Ayush,
I would like to inform you that our services are hosted on amazon servers and they have dynamic IP’s so we can’t share IP’s to our customers as they will prove no good to them.
Secondly, amazon maintains a list of IP’s whenever they update, this information is publicly available here : https://forums.aws.amazon.com/ann.jspa?annID=1701#
This is the best if you can add domain on firewall however if not supported, you can open TCP ports 443 and 80 for outbound.
Thanks,
Ashish