If you don't already have preferred DNS servers, consider using the servers offered by opendns.com 208.67.222.222 and 208.67.220.220
You can find a list of free public DNS servers here
$Id: dsl.html,v 1.6 2019/11/15 18:37:39 thegiant Exp $ Configuration and Use of SDF's DSL INTERNET Service - traditional link (using RCS)