A few days ago I noticed that I could not use my OPNsense firewall as a SSH jump host to my other servers. I’m not sure how long this issue has existed, or if it has always existed, but since I’ve had IPv6 connectivity after a long time of IPv4-only internet, I could definitely feel the consequences.

While ssh root@opnsense worked perfectly, ssh -6 root@opnsense failed with a timeout. Verbose output of the ssh command showed that the client was trying to access the correct IPv6 address of my firewall, but obviously it did not receive any response.

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It happened again - this time on my Fedora machine! I ended up with a laptop that won’t boot after some package changes. Last time that happened was ~ 4 years ago when Arch Linux could not decrypt my main partitions due to some changes on a crypto library. This time the accident was caused by a simple dnf command:

dnf autoremove

I intended to remove dangling packages from my system - expecting my package manager to know which packages are needed and which not. Unfortunately some really important packages (amongst some legacy packages) were removed. My laptop was not even able to start any boot loader - it booted straight to the device diagnosis application that the hardware manufacturer ships.

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Lately I switched from a binary Ejabberd package to a self-built version of Ejabberd on my XMPP server trashserver.net. This was done mainly because the “Debian Backports” repository did not offer the version of Ejabberd that I urgently needed. While the repo was stuck at 20.02, I wanted to provide the users 20.04 to be able to drastically improve the user experience during video calls.

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By default your Debian server will try to deliver system / Cron emails to your mailbox server directly. While this is convenient for very simple setups, you might run into trouble if your inbox server expects DKIM-signed mails or does not accept emails from every IP address, but only from mail senders with good reputation. For that reason I’m running a single, well configured email gateway server, which is forwarding the mails from all my hosts into the internet. But how to tell all the hosts to send their mails via a central gateway? Installing and configuring Postfix is one way …

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If you follow my Mastodon account, you might know that I like IPv6 very much. I’m trying to do my best to offer all my services via the new IP protocol. Lately I was investigating the use of IPv6 in my server network. Unfortunately the result was quite disappointing:

Bad IPv6 statistics

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