Can't connect to MySQL from PHP, but is able to connect from remote machine?

Question

I really can't figure out this. Under a certain user, I am able to connect to the MySQL db on machine A from machine B, but I can't connect locally from machine A itself or connect from PHP.

To illustrate, I created a db MYTEST on machine A. Then I create a user MYTEST and grant all privileges on MYTEST:

GRANT ALL PRIVILEGES ON MYTEST.* TO 'MYTEST'@'%' IDENTIFIED BY 'mypass';
FLUSH PRIVILEGES;

I did these as root, which I can connect from anywhere without any problem. Result:

Then, I try to connect from another machine, machine B:

ubuntu@ip-*-*-2-153:~$ mysql -u MYTEST -p -h *.*.*.174
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 84
Server version: 5.5.32-0ubuntu7 (Ubuntu)

Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql>

These all look good. Now I go back to machine A and do this:

root@wangboyang:~# mysql -u MYTEST -p
Enter password:
ERROR 1045 (28000): Access denied for user 'MYTEST'@'localhost' (using password:
 YES)
root@wangboyang:~#

Whereas I'm able to connect as root:

root@wangboyang:~# mysql -u root -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.

Ultimately, I need to connect from PHP. It doesn't work either:

php > $con = mysqli_connect('128.199.253.174', 'MYTEST', 'mypass');
PHP Warning:  mysqli_connect(): (28000/1045): Access denied for user 'MYTEST'@'w
angboyang.com' (using password: YES) in php shell code on line 1

I have to use root:

php > $con = mysqli_connect('128.199.253.174', 'root', 'somepasswordhere');
php >

I then tried something aggressive. I granted all global privileges to MYTEST, but all the results remained the same. Please anyone has any idea? Would Really appreciate it.

Note:

1. I'm sure the password is correct. To confirm this I used the same password as the root and compared the hash to be the same. I can connect using root. So the password is correct.

2. Both machines Ubuntu 13.10.

3. I tried to flush privileges and restart mysql server in between all these steps but to no avail.

Answer 1

I managed to solve the problem but I don't really understand why.

The problem seems to be the wildcard '%'. It should be able to substitute user connecting from any IP, domain.

However, it doesn't work for the case of 'localhost' and 'mydomain.com'. My guess is that either '%' only matches IPs or the behaviour is specified somewhere in the doc or config file.

To solve it, create user 'MYTEST'@'localhost' and 'MYTEST'@'domainname.com'.