ERR_ECH_REQUIRED

• Server serves HTTPS resource record with ECHConfig but client skipped it
• DNSSEC validation failed for HTTPS RR (intermediate resolver stripped)
• ECHConfig expired (server rotated public key)
• Client on old Chrome version (<115)
• Enterprise proxy strips HTTPS DNS records

1. Update Chrome ≥ 115
2. DNS provider support HTTPS records: Cloudflare ✅, Route 53 ✅, most 🟡
3. Enable DNSSEC on domain
4. Server-side: chrome://flags/#encrypted-client-hello toggle
5. Enterno SSL checks HTTPS record presence

Check SSL Certificate →

• ERR_SSL_PROTOCOL_ERROR
• NET::ERR_CERT_AUTHORITY_INVALID
• All SSL errors

The ERR_ECH_REQUIRED error indicates that the server requires the use of Encrypted Client Hello (ECH) for secure connections, and your browser does not support this feature. To resolve this issue, ensure that your browser is updated to the latest version, or switch to a different browser that supports ECH, such as recent versions of Chrome or Firefox. If you are managing the server, ensure that ECH is properly configured in your server settings.

Encrypted Client Hello (ECH) is an extension of the TLS protocol that enhances privacy by encrypting the initial handshake data sent from the client to the server. This is crucial in preventing eavesdropping and tampering during the connection setup phase. ECH is particularly relevant as more organizations adopt privacy-focused practices, and it is supported by several modern web browsers.

When a user attempts to establish a secure connection without ECH support, the server may respond with the ERR_ECH_REQUIRED error. This typically occurs when the server is configured to require ECH for all incoming connections, which can be a common practice among websites that prioritize user privacy and data security.

How ECH Works

With ECH, the client's initial handshake is encrypted, allowing sensitive information such as the hostname being accessed to remain confidential. Here’s a simplified overview of the ECH handshake process:

1. The client sends an encrypted ClientHello message containing a randomly generated key.
2. The server decrypts this message and processes the connection request.
3. The server sends back a response, which is also encrypted, completing the handshake.

Because of this encryption, traditional network monitoring methods cannot easily inspect the contents of the handshake, thus enhancing privacy.

To avoid the ERR_ECH_REQUIRED error and ensure that your server supports ECH, you need to configure your web server appropriately. Below is an example configuration for Nginx, which has been updated to support ECH:

server {
    listen 443 ssl;
    server_name example.com;

    ssl_certificate /path/to/certificate.crt;
    ssl_certificate_key /path/to/private.key;

    # Enable ECH
    ssl_conf_command ECH on;

    location / {
        proxy_pass http://backend;
    }
}

In this example, the `ssl_conf_command ECH on;` directive enables ECH support on your Nginx server. Make sure to replace `/path/to/certificate.crt` and `/path/to/private.key` with the actual paths to your SSL certificate and private key.

For Apache servers, the configuration would look like this:

<VirtualHost *:443>
    ServerName example.com

    SSLEngine on
    SSLCertificateFile /path/to/certificate.crt
    SSLCertificateKeyFile /path/to/private.key

    # Enable ECH
    ECH on;
</VirtualHost>

Once you have updated your server configurations, restart the server to apply the changes. Ensure that your clients are also using browsers that support ECH to avoid the ERR_ECH_REQUIRED error.

For testing ECH support, you can use tools like ECH.dev to verify if your server is correctly configured and can handle ECH requests. This proactive approach will help mitigate potential connectivity issues for users accessing your site.

The ERR_ECH_REQUIRED error occurs when a web server requires Encrypted Client Hello (ECH) support, but the client (browser) does not support it. To resolve this issue, ensure that your browser is updated to the latest version that supports ECH, or configure your server to disable ECH if it's not necessary for your use case.

When encountering the ERR_ECH_REQUIRED error, it's essential to identify the browser and its version, as ECH support varies across different platforms. Below are some troubleshooting steps tailored for popular browsers:

Google Chrome

• Ensure you are using Chrome version 92 or later, as ECH support was introduced in this version.
• To check your version, navigate to chrome://settings/help.
• If you are on an earlier version, update Chrome through the settings menu.

Mozilla Firefox

• Firefox introduced ECH support in version 94. Check your version by going to about:support.
• Update Firefox if you are using an older version.

Microsoft Edge

• Edge users should ensure they are on version 92 or newer.
• Check your version using edge://settings/help.

If all browsers are updated and the error persists, consider testing in incognito mode to rule out extensions that might interfere with ECH.

To effectively handle the ERR_ECH_REQUIRED error, proper server configuration is crucial. Implementing ECH involves updating your server's TLS settings. Here’s a practical example using Nginx:

Nginx Configuration

server {
    listen 443 ssl;
    server_name example.com;

    ssl_certificate /path/to/certificate.pem;
    ssl_certificate_key /path/to/private.key;
    ssl_protocols TLSv1.3;
    ssl_early_data on;
    ssl_ecdh_curve X25519:secp256r1;
    ssl_ciphers 'ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256';
    # Enable ECH
    ssl_ech on;
}

In this configuration:

• The server listens on port 443 with SSL enabled.
• Ensure that the server uses TLS 1.3, as ECH is supported only in this version.
• Set the ssl_ech directive to on to enable ECH support.

After making these changes, test your configuration using tools like SSL Labs to verify ECH support. If the test indicates that ECH is not supported, double-check your server and client configurations.