tags: network firewall settings whitelist IP address range App Engine.
References: https://cloud.google.
For the eyos retail client to access the cloud from the till and send receipts, it needs to connect to the https://www.yreceipts.com (US data center) or https://yreceipts-prod-uk.appspot.com (EU data center).
Our cloud system runs on top of various google cloud services, so for firewalls which require a static IP address range, there are a number of IP addresses which need to be whitelisted.
Note that using static IP address filtering is not considered a safe and effective means of protection. For example, an attacker could set up a malicious google service which could share the same IP address range as the eyos retail cloud application.
Google publishes a list of all IP addresses available to be used by all customers & services in Google Cloud. You can find this list here - https://www.gstatic.com/ipranges/goog.json
All outbound connections from the eyos system will come from one of the those google IP addresses. All inbound connections to eyos will go to one of those google IP addresses.
NB: The IP ranges in this list are subject to change without notice, a one time import of these IP addresses is likely to become out of date quickly. You must update any rules based on these IP addresses often.