As mentioned here, having a Reverse PTR record is key for successful email sending and delivery from one's own server. In order to check if it's correctly set for my server, I tried:
dig -x 220.127.116.11 # replace with the IP of a server
but the answer is:
; <<>> DiG 9.9.5-3ubuntu0.1-Ubuntu <<>> -x 18.104.22.168 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 29789 ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;xxx.xxx.xxx.xxx.in-addr.arpa. IN PTR ;; Query time: 27 msec ;; SERVER: 127.0.0.1#53(127.0.0.1) ;; WHEN: Sun Sep 10 14:51:32 CEST 2017 ;; MSG SIZE rcvd: 54
I don't see anything that looks like a Reverse PTR record.
I tried with various IPs obtained from well-known websites:
dig -x 22.214.171.124 (obtained from
ping stackoverflow.com), and it looks the same.
Why can't I see any Reverse PTR record with