Not receiving email from certain recipients DNS doesn't resolve

[Reza Jelveh]

I can't figure out how the DNS works.

I cannot send or receive emails from cigna.com who knows possibly other emails as well.

ubuntu@box:~$ ping cigna.com
ping: cigna.com: Temporary failure in name resolution

How can I fix this?

[Kiru Mondictwtz]

Can you post the output from 'sudo cat /etc/resolv.conf'

Also check if you can ping 1.1.1.1, or 8.8.8.8

[Reza Jelveh]

I can ping both.

ubuntu@box:~$ sudo cat /etc/resolv.conf
nameserver 127.0.0.1

I can resolve with the cloudflare resolve using dig

ubuntu@box:~$ dig @1.1.1.1 cigna.com                                                  [5/56]

; <<>> DiG 9.18.12-0ubuntu0.22.04.2-Ubuntu <<>> @1.1.1.1 cigna.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 41285
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;cigna.com.                     IN      A

;; ANSWER SECTION:
cigna.com.              30      IN      A       170.48.10.90
cigna.com.              30      IN      A       170.48.29.90

[Kiru Mondictwtz]

Your dig output lends me to believe you've been blacklisted by the cigna email server.

[Kiru Mondictwtz]

This site might help
https://mxtoolbox.com/

[Reza Jelveh]

What do you mean? Something doesn't resolve properly.

ubuntu@box:~$ ping cigna.com
ping: cigna.com: Temporary failure in name resolution

postfix/smtp[25916]: B0FAF8C20D: to=[e-mail], relay=none, delay=10, delays=0.17/0.1/10/0, dsn=4.4.3, status=deferred (Host or domain name not found. Name service error for name=cigna.com type=MX: Host not found, try again)

[Kiru Mondictwtz]

You're right. I didn't see your dig via cloudflare.

We appear to be in the same situation. If you dig cigna.com directly do you get a communication error?

[babywhale321]

if you just made the domain + just got everything set up, i find that you get put on a blacklist but after time they will drop you from the black list. try what kirutian said and use https://mxtoolbox.com/ to scan your domain / ip

[Reza Jelveh]

My Domain is fine I'm not in a blacklist the mail server has been around for a very long time. I just recently updated and moved to glue records. No blacklist

…

On Fri, Jul 21, 2023, 10:54 babywhale321 ***@***.***> wrote: if you just made the domain + just got everything set up, i find that you get put on a blacklist but after time they will drop you from the black list. try what kirutian said and use https://mxtoolbox.com/ to scan your domain / ip — Reply to this email directly, view it on GitHub <#2286 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAAEFT2NJPIMJZACKNFXTETXRHVNNANCNFSM6AAAAAA2RVVHAE> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[test2a]

I had the same exact issue. A particular website was unable to send me emaild for a long time.

I once found the webmaster email but nothing. It would return as not found.

Then, very recently I sent a bunch of emails on their donotreply and believe me, somehow it worked and I am getting all emails now.

I was having trouble with only 1 email so who knows.

At the same Time, I would say, I had tried to send email to webmaster from gmail and yahoo, only gmail had not failed but I got no response so that makes me believe it was problem on their end.

Maybe you can try this? No harm in sending emails to DNR

[Kiru Mondictwtz]

OP check the output from

nslookup cigna.com

and

drill -DT cigna.com