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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 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 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 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 5.3.2.3, “Password Hashing in MySQL”.


User Comments

Posted by robert fritz on September 13 2006 9:29am[Delete] [Edit]

Hello,

the error message "Client does not support authentication protocol" is also caused, if the client does not find the proper libmysql.dll. if the libmysql.dll is installed in different versions on the client-computer, maybe the client finds an older version of libmysql.dll and the connection fails. make sure, that the client uses the proper dll (check it for instance with with filemon.exe).

Posted by Vladimir Burdeiny on November 26 2006 9:07am[Delete] [Edit]

Linux
There was the same problem when using phpMyAdmin-2.9.1.1
check if it exist /lib/libmysqlclient.so
if no shell>cp mysql/lib/mysql/libmysqlclient.so /etc/libmysqlclient.so
###copy *.so from last compiling

Posted by Thuy Giuru on October 15 2007 11:53pm[Delete] [Edit]

I have this problem and reseting password solves it. Just log in as root user and run the SET PASSWORD...

I am using:
PHP version 4.4.7
MySQL version 4.1.22-standard

No problem when using phpMyAdmin 2.11.0

Posted by Shivaraj Tenginakai on November 4 2007 9:08am[Delete] [Edit]

Though I had mysql-5.0 client libraries installed, I still encountered this problem while using Perl DBI.

'strace' revealed that an old version of libmysqlclient.so was being picked up from another location.

Replacing the old libraries with 5.0 versions, and rebuilding DBD-mysql fixed the issue.

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 Paul Dunlop on June 30 2009 2:55pm[Delete] [Edit]

I had this error on a VPS dapper machine.

I had to upgrade php5.1.2 to php5.3

the --with-mysql=/usr/include/mysql required me to install the development libraries.

I had installed the incorrect ones.

by default you will get mysql-server v5 with dapper.

you need libmysqlclient15-dev_5.0.21-3ubuntu1_i386.deb to compile php correctly against this version.

thats a sudo apt-get libmysqlclient15-dev not the libmysqlclient12-dev I had stupidly done.

also I believe the php language / mysql_connect function will be dropping support for the OLD PASSWORD authentication as of php5.3:
from
http://au2.php.net/manual/en/migration53.incompatible.php

"The new mysqlnd library necessitates using MySQL's newer 41 bytes password format. Continued use of the old 16 bytes passwords will cause mysql_connect() to produce the following error message: "mysqlnd cannot connect to MySQL 4.1+ using old authentication". "

so be careful with the initial fix mentioned in this dated thread.

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