How can I check if my DNS mail system is working?

I reconfigured my DNS SPF settings to correct a message that was saying " The number of lookups on your SPF record exceed the allowed limit of 10. This will result in emails failing SPF authentication After the correction to the SPF record, I no longer get this message nor any other error. However, I would like to check to see if it is indeed working properly. How can I check this>