Question: I use MySQL 4.1 or MySQL 5.0, and when I try to authenticate my user, I get the following error:
Warning: mysql_connect() [function.mysql-connect]: client does not support authentication protocol requested by server; consider upgrading
Answer: In MySQL 4.1 there’s a new type of authentication different from the one used in 4.0 or 3.23, and PHP isn’t compiled for this version, so it can’t connect. There are a few different solutions, the first would be to compile PHP against the MySQL 4.1 client library. If that doesn’t work or you’re not allowed to do that, then you can read http://dev.mysql.com/doc/mysql/en/old_client.html on how to fix it. Basically, you need to save the pandora user password with an old hashing algorithm:
mysql> set password for 'pandora'@'localhost' = old_password('pandora');