A condition of being granted a .gov.wales or .llyw.cymru sub domain is that you setup and maintain DMARC through creating and maintaining the necessary TXT records in your DNS.
Os yw CNC a/neu’r Awdurdod Lleol wedi cadarnhau nad oes angen trwydded, rhaid cadw’r dystiolaeth hon hefyd a sicrhau ei bod ar gael i’w dangos.