Hmm, so we get
% nslookup de.archive.ubuntu.com ns1.canonical.com
...
de.archive.ubuntu.com canonical name = ubuntu.mirror.tudos.de
** server can't find ubuntu.mirror.tudos.de: REFUSED

And tudos.de seems associated with TU Dresden, but well, no DNS entry to find. Though at least the domain does not seems to be up for grabs. 🤔

#ubuntu #tudresden #tudos_de #aptget