hostnamectl set-hostname your-fqdn ivnilv@sa584:~$ dig MX gomastodon.social ; <<>> DiG 9.16.1-Ubuntu <<>> MX gomastodon.social ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 9541 ;; flags: qr rd ra; QUERY: 1, ANSWER: 5, AUTHORITY: 0, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 65494 ;; QUESTION SECTION: ;gomastodon.social. IN MX ;; ANSWER SECTION: gomastodon.social. 1528 IN MX 15 eforward4.registrar-servers.com. gomastodon.social. 1528 IN MX 20 eforward5.