https://www.kevinhorst.de/tags/sieve/Recent content in Sieve on KevinHorst ITHugo -- gohugo.ioeninfo@kevinhorst.de (Kevin)info@kevinhorst.de (Kevin)This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.Mon, 01 Jan 0001 00:00:00 +0000https://www.kevinhorst.de/posts/filter-google-groups-spam-with-sieve/Mon, 15 Sep 2025 00:00:00 +0000info@kevinhorst.de (Kevin)https://www.kevinhorst.de/posts/filter-google-groups-spam-with-sieve/<p>Lately, more and more spam mails have been showing up in my inbox disguised as legitimate business inquiries (&ldquo;Inquiry&rdquo;, &ldquo;Request for quote&rdquo;, &ldquo;Anfrage zu Ihrem Produkt&rdquo;) and sent through a Google Group. Technically they come from <code>googlegroups.com</code> infrastructure, with valid SPF and DKIM signed by Google, so reputation-based filters tend to let them through. The giveaway sits in the headers: <code>List-Id</code> and <code>List-Unsubscribe</code> point at <code>googlegroups.com</code>, and there is an <code>X-Google-Group-Id</code> header. A real customer inquiry sent to a business address never carries those - which is exactly what the Sieve filter below targets.</p>