[otrs] (no mail exchanger (mx) found!)!

I see in posts that I need to change the setting: "I think OTRS checks whether the entered customer mail-address seems to be valid through checking whether a MX-DNS-record could be found. To turn off this behaviour, set Framework -> Core: CheckMXRecord = No " Where exactly do I put: set Framework -> Core: CheckMXRecord = No What file does this go in specifically and where?