
This alternate configuration allows you to control the "failmode" - this dictates how the system will act if network communication with Duo is interrupted. If your organization requires IP-based rules, please review this Duo KB article. Firewall configurations that restrict outbound access to Duo's service with rules using destination IP addresses or IP address ranges aren't recommended, since these may change over time to maintain our service's high availability.

This application communicates with Duo's service on TCP port 443.
