Today I received another email from the Let’s Encrypt Expiry Bot that one of my certificates on my Synology NAS will expire in 0 days. Mmmm… that’s odd. I thought that the certificate automatically will be renewed every 3 months. So I logged in the DSM interface, went to de certificate store and indeed. The certificate will expire tomorrow. But wait a minute… why is the certificate not renewed? Well…. I have a simple website on a Raspberry Pi, on a different subnet, forwared with port 80 on my router. And what port does Let’s Encrypt use for (re)new the…
