Hi
Does anyone here know how U.S. customs works at DFW if the passenger is arriving from outside the U.S. and the final destination is also outside the U.S.?

My itinerary is GUA-DFW-LAX-SYD with a fairly tight connection in DFW. Is it possible to check the bag all the way through to SYD or will it be necessary to claim and re-check it in DFW?

Many thanks
SPS