Error 1043 ER_HANDSHAKE_ERROR indicates the client and MySQL server could not negotiate a valid connection handshake, often due to mismatched protocols, SSL issues, or network interruptions.
MySQL Error 1043: ER_HANDSHAKE_ERROR means the initial client-server handshake failed, so the session never starts. Check MySQL version compatibility, SSL settings, and network firewalls. Restart the connection with matching credentials to resolve the issue.
Bad handshake
The error string "Bad handshake" appears when the MySQL client and server cannot complete their initial handshake. The connection closes before authentication, so no SQL runs.
Error 1043 belongs to SQLSTATE 08S01, marking a communication link failure. Fixing it restores connectivity and prevents application downtime.
Protocol mismatches between client and server versions often trigger a bad handshake.
A 5.7 client talking to an 8.0 server with deprecated features disabled will fail quickly.
Broken or misconfigured SSL/TLS settings can block the TLS handshake stage, producing the same 1043 code.
Firewalls, proxies, or load balancers that tamper with TCP packets may interrupt the handshake bytes, forcing MySQL to abort.
Incorrect character set or collation negotiation, especially with older JDBC or ODBC drivers, can also surface this error.
First, confirm both client and server binaries come from compatible major versions.
Align them or enable the --colonel_compatibility flag if your distro provides it.
Second, test SSL off and on. If disabling SSL fixes the issue, regenerate certificates with matching CNs and enable require_secure_transport=ON.
Third, inspect networking rules. Allow inbound and outbound traffic on the MySQL port (default 3306) from the application host and ensure no middlebox rewrites packets.
Fourth, review authentication plugins. A client expecting mysql_native_password will fail against a server defaulting to caching_sha2_password.
Install the new plugin or set default_authentication_plugin appropriately.
Upgrading AWS RDS MySQL from 5.7 to 8.0 often breaks legacy PHP mysqlnd clients. Upgrade the client library or set the DB parameter group auth plugin to mysql_native_password.
Docker setups with SSL offload at the proxy can inject extra bytes. Bypass the proxy or use TCP mode instead of HTTP mode in HAProxy.
Pin client and server versions in your deployment manifests and upgrade them together.
Run integration tests after every minor upgrade.
Automate certificate rotation and validation. Tools like certbot or Vault can keep TLS settings consistent.
Use monitoring solutions, or Galaxy's query metadata scanner, to alert on sudden spikes in ER_HANDSHAKE_ERROR codes.
Error 1040 Too many connections happens when the server accepts the handshake but has no threads left. Increase max_connections.
Error 2013 Lost connection to MySQL server during query occurs after the handshake. Tune wait_timeout or network MTU.
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No. SSL issues are common, but version and authentication mismatches or packet loss can also trigger the error.
You can, but it weakens security. Regenerate certificates and validate CA chains instead of disabling SSL.
Galaxy’s connection wizard tests SSL, authentication plugin, and MySQL version compatibility before saving the connection, preventing most handshake failures.
No. The error exists in all supported MySQL versions, but new default auth plugins in 8.0 make it more visible.
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