HedgeDoc is a Web application that provides a collaborative notepad. Things like an online family notepad to write grocery lists or plan the next trip can be realized. It is pretty easy to self-host this tool on a Raspberry Pi using Docker. Unfortunately, there is no official Docker image for ARM. Instead one has to use the one from linuxserver.io or build the image on your own. When testing the linuxserver. Read more

Yesterday I played a bit with Synapse, the reference implementation of a Matrix homeserver. Matrix is a federate chat protocol that features end-to-end encryption and does not require a phone number. As it is federated, everyone can run their own server but still talk to users registered to other servers. So, in my eyes, Matrix should be preferred over Signal or comparable applications. The installation would actually be simple if the documentation were better. Read more

Since 2010, I guess, I run Owncloud and later Nextcloud on different small “servers” in my home network. Recently, I had the impression that my instance, which I updated/upgraded many times, got a bit bloated and some things simply did not work correctly anymore. The other day I decided that it is time to setup up a new instance from scratch. However, this time I did not want to have a complicated native installation running on nginx, php-fpm, mySQL, Redis and whatever dependency my old Nextcloud instance had. Read more

A subscriber of my blog (most probably the only one :D) recently made me aware that it won’t deliver a full RSS feed. I looked into this matter and found this highly helpful Hugo helpfile hidden somewhere in the Hugo the documentation (please note the slight irony). To enable a full RSS feed, do the following: Download the default Hugo RSS feed template and place it in some path/file mentioned here. Read more

My homebrew had some issues with an outdated version of Command Line Tools (CLT). I tried to update the CLT manually using sudo xcode-select --install but the installer told me, that CLT could not be found on the Apple servers. Strange. I tried uninstalling CLT with sudo rm -rf /Library/Developer/CommandLineTools (this is Apple’s intended way of uninstalling the stuff) and installing it again with sudo xcode-select --install. Same situation. Now I rebooted the machine. Read more

Recently I discovered that I have access to Office 365 through my university. I am not interested in Office 365 at all, but my subscription includes 5 Terra (yes!) Bytes of OneDrive storage. This has aroused my full interest. But: the official OneDrive client is not really what I want, because I don’t want to synchronize stuff from a folder on my hard drive with OneDrive. I would like to “mount” OneDrive and use a tool, preferably BorgBackup or something similar, to transfer encrypted snapshots to OneDrive. Read more

When you are using the 3.8-* version of xtables-addons to harden your server with a geofense, chances are super high that things don’t work anymore… The latest problem occurs after you have downloaded the geo-ip-tables from Maxmind and try to convert the tables for the geofense with xt_geoip_build. You get this error: Can't open DBIP database. The simple reason for this is that the developers of xtables-addons decided to get rid of Maxmind (maybe because they did that thing with the user accounts a couple of months ago? Read more

If you are running a Linux server, you probably want to enable that thing to send emails to you. This is useful, for instance, to tell you that someone got blocked by fail2ban. In earlier years, SSMTP has been a good candidate to achieve this kind of thing. Today, Debian, Raspbian, and probably Ubuntu server OSes have no packet for SSMTP anymore. However, you can use MSMTP to achieve the same thing. Read more

Since some time I use a geofence on my servers to ban all incoming requests that do not originate from DE. The company (Maxmind) that distributes up to date mappings from IP ranges to country codes (“geoip tables”) recently changed how they distribute these files. Now, you must have an account and license key to download the geoip tables. Note: everything is still free! The need for login credentials breaks the update mechanism for geoip tables which typically uses xt_geoip_dl. Read more

Some days ago I had the idea to dig around in my mailbox and see what people have sent me over the years. As I was especially interested in the attachments (pictures) I googled a bit and found out you can quickly extract stuff from a mbox (used by a Dovecot SMTP server). Here’s what I cobbled together. #!/usr/bin/python import mailbox import dateutil.parser from datetime import datetime mbox = mailbox.mbox('/home/USER/mail/MAILBOX') def extractattachements(message): if message. Read more