Marfeel is an advertising company of which I have no relation, but it seems that some websites use their CDN to serve content and blocking the domain ssl.marfeelcdn.com makes them inaccessible, since when blocking ads at DNS level many resolvers (systemd-resolved, Unbound and Knot Resolver are the ones I know with this behavior) will prevent clients from accessing a domain that has a CNAME record pointing to a blacklisted domain.

I open this issue only to inform about this problem and evaluate if it would be convenient or not to remove this domain from the blacklist.

This is the list of websites that I have found with this problem:

• https://www.ghacks.net
• https://www.gizchina.com
• https://www.lainformacion.com

But any website that has followed these instructions is affected by this.