Thank @reinob for your answer. I also don't know which resolver I have installed. I don't have unbound installed because I got the following information with aptitude:
I got the following answer:
So, I followed your suggestion and I use the UFW firewall to disable the access to the port 53 from outside. This solves the problem ![:D]( "Very Happy")
Code:
root@degu02:~# aptitude show unboundPackage: unbound Version: 1.17.1-2+deb12u2 State: not installed ...Code:
$ dig cert-bund.de @X.X.X.X; <<>> DiG 9.18.24-1-Debian <<>> cert-bund.de @X.X.X.X;; global options: +cmd;; Got answer:;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 9300;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 5, ADDITIONAL: 1;; OPT PSEUDOSECTION:; EDNS: version: 0, flags:; udp: 1232;; QUESTION SECTION:;cert-bund.de.INA;; ANSWER SECTION:cert-bund.de.300INA35.234.91.239;; AUTHORITY SECTION:cert-bund.de.3600INNSbamberg.bund.de.cert-bund.de.3600INNSdns-1.dfn.de.cert-bund.de.3600INNSxenon.bund.de.cert-bund.de.3600INNSargon.bund.de.cert-bund.de.3600INNSnuernberg.bund.de.;; Query time: 36 msec;; SERVER: X.X.X.X#53(X.X.X.X) (UDP);; WHEN: Mon Mar 18 19:59:35 CET 2024;; MSG SIZE rcvd: 172
Statistics: Posted by 818erm9x1 — 2024-03-18 19:11