Mynacol’s Personal Blog

Earlier this year I brought an old laptop to my home my grandfather once gave. It is a relict from roughly 1999, with which I’ve already played around some nine years ago. Prior to 38C3 I had the idea to bring it to the congress so people could mess around with it. In the end, I was the one messing around with it, fighting to get some operating systems installed on this poor thing. ...

Since some weeks I got a strange error message from the Nextcloud client on startup: Changes in synchronized folders could not be tracked reliably. At first, I ignored it, but I noticed Nextcloud wouldn’t sync local changes reliably to the server. After I lost a git commit (yes, I sync some git repos over Nextcloud), I took the issue seriously. I knew this was related to a Linux feature called inotify. With it, you can monitor files or directories and get notified by the kernel whenever the selected events happen on those elements. I searched the Nextcloud client and nixpkgs changelogs, but didn’t find anything related to my problem. Then I searched in the Nextcloud client source code and found the dialog I saw. However, that didn’t help me either. ...

Mail clients are notorious for sending information not really required for mail conversations. They leak their identity and version number, sometimes even the operating system in User-Agent and X-Mailer headers. They leak the locally set time zone in the Date header. And sometimes they leak the private IP addresses during mail sending. Here I document some settings to hide this information in my preferred mail clients. Note: Hiding this metadata might not be enough to fully disguise your choice of mail clients. The ordering of mail headers was not tackled, behavior with attachments varies equally high and other details disclose the mail client identity. ...

I’m using NixOS since over a year for most of my server stuff and I’m loving it. One of the missing services was my email setup, originally deployed on Debian 10, later upgraded to Debian 11. I followed a setup guide and was quite happy, tweaking it over the years to my needs. Roughly, the software stack consists of Postfix as the MTA (“SMTP server”), Dovecot as the MDA (“IMAP server”) and rspamd including its requirement, redis, for spam protection and SPF/DKIM/DMARC verification as well as DKIM signing for outgoing mail. I avoided a webmail service to keep things simple and I already use standard mail clients across my personal devices anyway. ...