This recently has happened to us with our own Website and all our FGT.
When one tries to access our website all one gets in Chrome is a QUIC Protocoll error.
Looking at Chrome's netlog on a client affected I saw that it tried to use Cloudflare's ECH Protocoll to do encrypted client handshake to their proxy. This failed because UTM blocks cloudflare-ech.com.
If I add that FQDN to a policy that doesn't have filters and comes in front of the other internet policies our website works fine.
Cloudflare community also has a thread on this: https://community.cloudflare.com/t/err-ech-not-negotiated-problem/710760
I cannot say wether Cloudflare did something bad by enabling a feature they still declare experimental as default or not. (This is said in the linked thread).
However since non-filtering cloudlare-ech.com is not a solution (but a fix) I have openend a ticket with tac (which escalated to a senior with the first answer) aswell as with cloudflare support.
currently waiting for answers.
Thought I post this here just for if someone else runs into this issue :)
stay safe
Sebastian
--
"It is a mistake to think you can solve any major problems just with potatoes." - Douglas Adams
Nominating a forum post submits a request to create a new Knowledge Article based on the forum post topic. Please ensure your nomination includes a solution within the reply.
Thanks for sharing, Sebastian.
A new hard challenge for web filtering.
Few days ago I heard about twitter ban in Brazil, then twitter managed to bypass the restriction using Cloudflare. Now I understand.
Hi Sebastian,
As described on this link https://docs.fortinet.com/document/fortigate/7.6.0/administration-guide/405234/control-ech-tls-conne...
You could force Cloudflare to not use ECH if you use a DNS filter on FGT.
A DNS filter profile is applied that strips the ECH information from the DoH response, forcing the browser to use a non-ECH TLS connection.
Select Forum Responses to become Knowledge Articles!
Select the “Nominate to Knowledge Base” button to recommend a forum post to become a knowledge article.
User | Count |
---|---|
1502 | |
1013 | |
749 | |
443 | |
209 |
The Fortinet Security Fabric brings together the concepts of convergence and consolidation to provide comprehensive cybersecurity protection for all users, devices, and applications and across all network edges.
Copyright 2024 Fortinet, Inc. All Rights Reserved.