All traffic for the Backblaze Online Backup and B2 Cloud Storage services use the same IP ranges. The Backblaze datacenter servers are located at IP addresses in the following ranges (these are in "CIDR notation"):
If IPv4 notation is required, the above can be converted using a tool such as the one available here: https://www.ipaddressguide.com/cidr
All Backblaze servers use the *.backblaze.com or *backblazeb2.com domains, so it may be easiest to whitelist the appropriate domain(s).
NOTE: Backblaze is always adding more computers and so the following information WILL CHANGE in the future!
*Backblaze uses cloudflare for www.backblaze.com and help.backblaze.com, so you will see out of block addresses in use for those web pages.
Last updated: July 2019