While trying to remotely login to your MySQL server if you are getting this error: ERROR 1251: Client does not support authentication protocol requested by server; consider upgrading MySQL client then it means that you are still using mysql 4.1 or older versions on your computer while the MySQL server that you are connecting to is of higher version.
It is easy to solve this issue though.
First goto the MySQL Server machine or if it is not accessible, then SSH or remote desktop to the server machine.
Next in that server, login to your server locally and reach the mysql prompt.
Then run this command
SET PASSWORD FOR 'username'@'IPordomain' = old_PASSWORD('userpassword');
Here replace username with your username and replace IPordomain with the IP from which you will be logging in later. Then replace userpassword with your password.
That's it. You can now login again from your PC. What you just did is to let MySQL server know that you are still using the old password hashing mechanism for that particular user.