To grant the IP 192.168.2.4 to user mysqlguy
GRANT ALL ON *.* TO 'mysqlguy'@'192.168.2.4';
To allow any IPfor mysqlguy just use the wildcard % character
GRANT ALL ON *.* TO 'mysqlguy'@'%';
Also note it is normal and fine to have multiple entries in the mysql table.........