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B.5.2.5 Password Fails When Entered Interactively »
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B.5.2.4. Client does not support authentication protocol

MySQL 4.1 and up uses an authentication protocol based on a password hashing algorithm that is incompatible with that used by older 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 PASSWORD statement and the OLD_PASSWORD() function: 

    mysql> SET PASSWORD FOR
    -> 'some_user'@'some_host' = OLD_PASSWORD('newpwd');

    Alternatively, use UPDATE and FLUSH PRIVILEGES: 

    mysql> UPDATE mysql.user SET Password = OLD_PASSWORD('newpwd')
    -> WHERE Host = 'some_host' AND User = 'some_user';
mysql> 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:

    1. Start mysqld with the --old-passwords option.

    2. 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 Host and User values and assign a password using the OLD_PASSWORD() function and either SET PASSWORD or UPDATE, as described earlier.

Note

In PHP, the standard mysql extension does not support the new 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 will need to follow one of the options discussed above for configuring MySQL to work with old clients. The mysqli extension (stands for "MySQL, Improved"; new 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 newer MySQL client library for PHP. 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 5.4.2.3, “Password Hashing in MySQL”.

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User Comments

Posted by Kristiono Setyadi on May 14 2008 6:19am[Delete] [Edit]

If you are using PHPMyAdmin, just go the the "Privileges" tab.
Edit the user containing username and host you want to use with. In the "Change Password" box below, you can choose whether using password or no. The solution is in there: Choose "MySQL 4.0 Compatible" and "Go".

I have solved my problem using this simple way.

Posted by Max Power on August 17 2010 1:40pm[Delete] [Edit]

I had a 4.1 server which was still configured to generate only old passwords (16 digit) and a newer client which did not support old passwords. I could modify neither the server nor the client configuration.

On the client side, I used the following command to generate a 41-digit password:
SELECT PASSWORD('blablabla');

Then on the server side, I set the password to this 41-digit string:
SET PASSWORD FOR 'bob'@'somehost' = '*73C98624E32963F3D4828B9398FD3F67B8D58E40'

The client then connected flawlessly to the server.

Posted by Glenn Bullock on November 23 2010 8:27pm[Delete] [Edit]

I'm on Snow Leopard, Intel MacBook Pro, and finally had to install the mysql gem by hand (I was getting the "uninitialized constant MysqlCompat::MysqlRes" error).

The mysql download for Snow Leopard had the client libraries on board, I just had to give the ruby extconf.rb script the needed paths (ruby extconf.rb --with-mysql-dir=/usr/local/mysql --with-mysql-lib=/usr/local/mysql/lib --with-mysql-include=/usr/local/mysql/include), and make sure permissions on those files and directories were right.

I used the mysql-ruby-2.8.2.tar.gz version.

Once I make install-ed it, things worked. Thanks for all the help.

Posted by Toni Cordon Batlle on June 28 2011 10:10am[Delete] [Edit]

This can occurr if you set an incorrect "Plugin" on "User" table in "mysql" database.

Connecting from PHP using Authentication parameters, from a user with incorrect "Plugin", makes PHP can't connect, and shown the error message "Warning: mysql_connect() [function.mysql-connect]: Client does not support authentication protocol requested by server; consider upgrading MySQL client"

Best regards

Posted by Charles Peterson on June 4 2013 4:13pm[Delete] [Edit]

--secure-auth is default on after 5.6.?

you may need to disable this also if using an old mysql client.

http://dev.mysql.com/doc/refman/5.6/en/server-options.html#option_mysqld_secure-auth

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