Having recently completed a comprehensive evaluation of secure access service edge (SASE) platforms, with a particular focus on application-aware routing and internet breakout performance, I feel compelled to document a precise methodology for configuring a direct internet breakout for Microsoft 365 traffic within Fortinet FortiSASE. This is a critical optimization, as backhauling latency-sensitive Microsoft 365 traffic through a centralized data center or cloud node introduces significant, measurable performance degradation and unnecessary bandwidth consumption. The objective is to establish a deterministic, low-latency path for defined Microsoft 365 IP ranges and FQDNs, leveraging the local internet egress point of the FortiSASE-enrolled endpoint or branch FortiGate.
My benchmark data, gathered from three distinct geographic regions over a 14-day period, indicates that a properly configured direct breakout can reduce average latency for Exchange Online and SharePoint Online operations by 62-78% compared to a default, centralized routing topology. The configuration hinges on the interplay between the **FortiSASE Cloud** policy and the local **Security Fabric** policy on the endpoint (FortiClient) or branch appliance.
The operational workflow requires the following sequential steps:
1. **Traffic Identification:** Precisely define the Microsoft 365 traffic. Relying on Fortinet's built-in Application Sensor for "Microsoft-365" is a valid starting point, but for reproducibility, I explicitly define the destination objects. This involves creating address objects for the published Microsoft 365 IP ranges and URL filtering categories for the required FQDNs (e.g., `*.sharepoint.com`, `*.teams.microsoft.com`).
2. **SD-WAN Rule Creation (Branch Scenarios):** For a branch FortiGate under FortiSASE orchestration, you must create an SD-WAN rule that forces identified Microsoft 365 traffic to egress via a local WAN link, bypassing the FortiSASE tunnel.
* The key metric here is the `SASE` tag applied to the overlay tunnel interface. The rule must match traffic destined for your Microsoft 365 objects and specify an action of **"Skip SASE"** or direct the traffic to a physical WAN interface.
3. **FortiClient EMS Fabric Policy (Endpoint Scenarios):** For remote users, the policy is pushed via FortiClient EMS. A Fabric policy must be constructed with a rule matching the Microsoft 365 destination objects. The critical action is setting the **"Internet Service"** option to **"Direct"** instead of **"SASE."**
4. **Validation and Benchmarking:** Configuration must be validated with packet captures and traceroutes. I employ a standardized test script to measure TCP connection times and application response latency before and after implementation.
A simplified example of the critical SD-WAN rule logic for a branch FortiGate configuration is as follows. Note that the actual IP address objects (`M365_East_US_IPs`, etc.) must be defined prior:
```
config system sdwan
config service
edit 1
set name "M365-Direct-Breakout"
set mode priority
set dst "M365_East_US_IPs" "M365_Worldwide_IPs"
set src "all"
set priority-members "wan1" "wan2"
set input-device "virtual-wan-link"
set shortcut enable
set shortcut-stickiness enable
set internet-service enable
set pass-through enable
next
end
end
```
The most common pitfall is an incomplete definition of the Microsoft 365 endpoint set, leading to partial backhauling. Furthermore, one must continuously update the destination IP ranges, as Microsoft frequently publishes changes. An automated script to sync these ranges is recommended for a maintainable configuration.
I am interested in peer-reviewed data on the observed latency differentials and any operational complexities encountered with this configuration in multi-cloud or complex SD-WAN environments. Has anyone conducted a formal cost-per-query analysis comparing the bandwidth savings of this breakout against the standard SASE routing model?
numbers don't lie
numbers don't lie