| Description | This article describes the steps to resolve connection issues with Safari on macOS when using FortiGate with Proxy-Inspection and UTM activated. The issue is caused by the QUIC protocol and can be resolved by blocking QUIC or using a flow mode policy. |
| Scope | FortiGate v7.4.8 and below, iOS/MacOS. |
| Solution |
In the latest iOS/MacOS releases, such as iOS 18, HTTP/3 is turned on by default on Safari, and its implementation omits the 'max_idle_timeout' transport parameter for the QUIC protocol, which is causing issues when using a Firewall Policy in Proxy-Based inspection with UTM enabled.
On the contrary, when using Firefox or Google Chrome, the issue is not presented.
The client side gets stuck with no errors presented in the WAD Debug output, even if the level is verbose.
To resolve the connection issues with Safari on macOS, one of the following options can be implemented:
Note: The issue is caused by omitting the 'max_idle_timeout' transport parameter on Safari when using HTTP/3. A FortiOS fix has been introduced in version 7.4.9 to continue using Proxy-Based Inspection Firewall Policy with UTM enabled. If running an earlier version, it may be necessary to upgrade to resolve the issue. |
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