@carsten Something is off with your server. I have a lot of trouble with the official twtxt client’s Python AsyncIO to fetch your feed for a few days. Always get a ServerTimeoutError('Connection timeout to host https://yarn.zn80.net/user/carsten/twtxt.txt'). It turns out, both IPv4 and IPv6 addresses are resolved and the v6 one is preferred. However, connecting via v6 (2606:54c0:5540:18::14:2a4) fails and an attempt with v4 (81.172.204.59) is not made at all, the whole thing just aborts. :-( (I believe this is an error with aiohttp.)

curl, on the other hand does fall back to v4 automatically and then suceeds in getting your feed. It also attempts v6 first if I interpret the verbose output correctly. I temporarily monkey-patched the twtxt client to force IPv4 usage and was able to download your feed.

Now the really weird thing: Your firewall seems to block ICMP for v4, but not for v6. ping4 returns nothing, ping6 happily replies back. What the hell?