istio.io/content/en/about/faq/security/mysql-with-mtls.md

title	description	weight	keywords
MySQL Connectivity Troubleshooting	Troubleshooting MySQL connectivity issue due to PERMISSIVE mode.	95	mysql mtls

You may find MySQL can't connect after installing Istio. This is because MySQL is a server first protocol, which can interfere with Istio's protocol detection. In particular, using PERMISSIVE mTLS mode, may cause issues. You may see error messages such as ERROR 2013 (HY000): Lost connection to MySQL server at 'reading initial communication packet', system error: 0.

This can be fixed by ensuring STRICT or DISABLE mode is used, or that all clients are configured to send mTLS. See server first protocols for more information.