Both. Child support is enforced through state agencies, which notify the IRS through the Department of Treasury.
To find out if your returns have been marked for garnishment, call the Dept. of Treasury Bureau of Fiscal Services at call (800) 304-3107.
For more information, follow this link:
https://fiscal.treasury.gov/fsservices/gov/debtColl/dms/top/debt_top.htm
