

Client does not support authentication protocolMySQL 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 to 4.1, 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:
SET PASSWORD statement and the OLD_PASSWORD() function: mysql> SET PASSWORD FOR
-> 'some_user'@'some_host' = OLD_PASSWORD('newpwd');UPDATE and FLUSH PRIVILEGES: mysql> UPDATE mysql.user SET Password = OLD_PASSWORD('newpwd')
-> WHERE Host = 'some_host' AND User = 'some_user';
mysql> FLUSH PRIVILEGES;mysqld with the --old-passwords option.
mysql> SELECT Host, User, Password FROM mysql.user -> WHERE LENGTH(Password) > 16;
Host and User values and assign a password using the OLD_PASSWORD() function and either SET PASSWORD or UPDATE, as described earlier. For additional background on password hashing and authentication, see section 5.5.9 Password Hashing in MySQL 4.1.
