My Home Assistant started sending me a daily warning: Let's Encrypt certificate is expiring in 29 days, 28 days, 27 days - until I finally found time to investigate why the certificate is not renewing. And fix the issue.
Posted by ads' corner on Saturday, April 18, 2026
Was setting up a new Debian Bookworm system in my home environment. So far I was not using certificates at home, and wanted to change this along the way, using Let's Encrypt. Since the IP-addresses here are RFC1918, I can't use the http01 challenge, and have to resort to dns01 challenges. On Debian Bookworm, using certbot, this fails reproducible.
Posted by ads' corner on Monday, June 9, 2025