Re: multiple host not work

[Barry Galbraith]

123.123.123.123 isn't the /24 boundary.
You could try

 
Grant all on *.* to 'user1'@'123.123.123.0/255.255.255.0' identified by "password";

to specify all hosts in 123.123.123.0/24 network
You also need to enclose the username and network in quotes.
See the refman https://dev.mysql.com/doc/refman/5.7/en/account-names.html

Good luck,
Barry.