Client does not support authentication protocol
B.1.2.3. Client does not support authentication protocol
MySQL 5.0 uses an authentication protocol based on a password hashing algorithm that is incompatible with that used by older (pre-4.1) clients. If you upgrade the server from 4.0, attempts to connect to it with an older client may fail with the following message:
shell> mysql
Client does not support authentication protocol requested
by server; consider upgrading MySQL client
To solve this problem, you should use one of the following approaches:
- Upgrade all client programs to use a 4.1.1 or newer client library.
- When connecting to the server with a pre-4.1 client program, use an account that still has a pre-4.1-style password.
- Reset the password to pre-4.1 style for each user that needs to use a pre-4.1 client program. This can be done using the
SET PASSWORDstatement and theOLD_PASSWORD()function:mysql>
SET PASSWORD FOR->'some_user‘@’some_host‘ = OLD_PASSWORD(’newpwd‘);Alternatively, use
UPDATEandFLUSH PRIVILEGES:mysql>
UPDATE mysql.user SET Password = OLD_PASSWORD('->newpwd‘)WHERE Host = 'mysql>some_host‘ AND User = ‘some_user‘;FLUSH PRIVILEGES;Substitute the password you want to use for “
newpwd” in the preceding examples. MySQL cannot tell you what the original password was, so you’ll need to pick a new one. - Tell the server to use the older password hashing algorithm:
- Start mysqld with the
--old-passwordsoption. - Assign an old-format password to each account that has had its password updated to the longer 4.1 format. You can identify these accounts with the following query:
mysql>
SELECT Host, User, Password FROM mysql.user->WHERE LENGTH(Password) > 16;For each account record displayed by the query, use the
HostandUservalues and assign a password using theOLD_PASSWORD()function and eitherSET PASSWORDorUPDATE, as described earlier.
- Start mysqld with the
Note
In older versions of PHP, the mysql extension does not support the authentication protocol in MySQL 4.1.1 and higher. This is true regardless of the PHP version being used. If you wish to use the mysql extension with MySQL 4.1 or newer, you may need to follow one of the options discussed above for configuring MySQL to work with old clients. The mysqli extension (stands for “MySQL, Improved”; added in PHP 5) is compatible with the improved password hashing employed in MySQL 4.1 and higher, and no special configuration of MySQL need be done to use this MySQL client library. For more information about the mysqli extension, see http://php.net/mysqli.
It may also be possible to compile the older mysql extension against the new MySQL client library. This is beyond the scope of this Manual; consult the PHP documentation for more information. You also be able to obtain assistance with these issues in our MySQL with PHP forum.
For additional background on password hashing and authentication, see Section 5.7.9, “Password Hashing as of MySQL 4.1”.