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Whiteboards.io backend must be able to reach out to your Atlassian application in order to perform authentication of users and requests.
Firewall Rules
To allow Whiteboards to perform Oauth authentication with Atlassian products which are behind a firewall, you need to set up firewall whitelist rules that enable Whiteboards to connect on port 443 to your Atlassian product:
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Your firewall should allow this IP address to connect: 35.232.138.12