To grant the IP 192.168.2.4 to user mysqlguy
GRANT ALL ON *.* TO 'mysqlguy'@'192.168.2.4';
To allow any IP for 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.
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