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:
mysqlClient 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.
SET PASSWORD FOR->
some_host' = OLD_PASSWORD('
UPDATE mysql.user SET Password = OLD_PASSWORD('->
WHERE Host = 'mysql>
some_host' AND User = '
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:
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:
SELECT Host, User, Password FROM mysql.user->
WHERE LENGTH(Password) > 16;
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
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
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
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
For additional background on password hashing and authentication, see Section 18.104.22.168, “Password Hashing in MySQL”.