DMARC Capable Ziggo Zakelijk

Back in about March, I think I finished setting the various things DMARC up, and it seems that the reporting is behaving more-or-less correctly. However, when looking at my reports, I keep seeing “Ziggo Zakelijk” show up on my “DMARC capable” tab.

I have no idea what this (apparently) ISP is, and they’re not an authorized mail source… why do they appear here?

Thanks for the insight!

This might be them: Ziggo - Wikipedia As for why emails from that ISP show up, I do not know.