IP-adressen räcker i host-fältet.
Sedan måste brandväggen öppnas upp om du nu har brandväggen påslagen. Det måste fixas på båda datorerna förstås. Så här har jag skrivit i en installationsbeskrivning:
If you want to be able to access the database from other machines than the one MySQL is running on, you need to open the port used by MySQL. Go to System Preferences and select Sharing then select the Firewall tab. If the Firewall is on, you click the "New..." button and then for the "Port name" select "Other" and in the "Port Number, Range or Series"-field enter 3306. In the "Description" field you can enter MySQL. Close the System Preferences. If the Firewall is off you don't need to bother with this.
Hoppas det kan vara till hjälp...
/M