Incoming Mail problems

[mathias1]

Hi,

we have a problem that from some mailserver we do not receive mails.
the other mailserver returns the mail with the following error message:

Remote Server returned '554 5.4.0 < #4.0.0 smtp; 4.4.0 - Other network problem '[Errno 61] Connection refused' (delivery attempts: 0)>'

any idea what the problem is?
Port 25 is reachable from the internet and e.g. we receive mails from gmail.com

thanks

 

[Stoiko Ivanov]

please post the complete logs of such a transaction - and check the logs on both sides ...)

else the error sounds like there is either nobody listening on port 25 - or a firewall on the path rejects connection attempts

 

[mathias1]

port 25 is listeing an external access possible

this is the error:

Remote Server returned '554 5.4.0 < #4.0.0 smtp; 4.4.0 - Other network problem '[Errno 61] Connection refused' (delivery attempts: 0)>'

Ursprüngliche Nachrichtenköpfe:

X-IronPort-DK-Sig: DKIM_domain_de
Received: from ex2016-4.domainlocal ([10.40.15.15])
by mail1.domain.de with ESMTP/TLS/ECDHE-RSA-AES128-GCM-SHA256;
25 Nov 2022
07:54:23 +0100

 

[Stoiko Ivanov]

his is the error:

Remote Server returned '554 5.4.0 < #4.0.0 smtp; 4.4.0 - Other network problem '[Errno 61] Connection refused' (delivery attempts: 0)>'

where do you get this error - it does not look like a complete logline from PMG?!

 

[mathias1]

in pmg I do not see anything, no logs nothing. this error is from the remote mailserver.
could it be a TLS problem?

 

[Stoiko Ivanov]

in pmg I do not see anything, no logs nothing. this error is from the remote mailserver.
could it be a TLS problem?

connection refused usually refers to a closed port - so I'd say the issue is between the remote server and your PMG - maybe a firewall - maybe something with DNS not working out ...

in any case - you need to check the remote server's configuration and logs

 

[mathias1]

Port 25 is open, do I need other ports? still strange. I not receive emails from e.g. https://www.badische-zeitung.de/meine-bz/anmelden

 

[Stoiko Ivanov]

Port 25 is open, do I need other ports?

no - smtp over the internet uses port 25...

check that:
* your DNS Setup is correct - MX-record pointing to your PMG's hostname, PMG's hostname pointing to the public IP of your PMG
* check the logs of your PMG when subscribing to the newsletter - if there is a connection attempt it will show up in the logs

 

[mathias1]

MX is correct, we receive mails from other servers, only from two domains we do not receive the mails.
With my gmail.com account I receive mails from these domains. Could it be a TLS problem?

 

[Stoiko Ivanov]

Could it be a TLS problem?

as said - in my experience 'connection refused' usually points to a closed port (which might of course be due to a firewall in the path) - but I cannot tell since I neither have the complete logs from the sending side nor the mail-setup of the sending site...

You can of course disable TLS in the GUI, restart and try without....

 

[mathias1]

hello,

it seems that I have found the problem

my domain is abc.com
the mx for abc.com points to mx.xyz.com
mx.xyz.com points to PMG IP
--> does not work

if I change
mx abc.com to PMG IP
--> everything works.

do you have any idea why this happens?

thanks

 

[Stoiko Ivanov]

do you have any idea why this happens?

not really - and without knowing the domain it's not really possible to take a look where the issue might be..
you can always use `dig` and `dnstracer` to get a better picture
or contact your DNS provider - they might be able to spot problems.

anyways I think mx records should not point to IPs but rather to hostnames (as you had configured it, where it did not work) - see e.g.:
https://serverfault.com/questions/663112/why-cant-mx-records-point-to-an-ip-address

 

[mathias1]

Hi,

this works:

dig extraabi.de MX

; <<>> DiG 9.11.3-1ubuntu1.18-Ubuntu <<>> extraabi.de MX
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 10439
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;extraabi.de. IN MX

;; ANSWER SECTION:
extraabi.de. 11 IN MX 10 mail.extraabi.de.

;; Query time: 0 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Fri Dec 09 12:21:29 CET 2022
;; MSG SIZE rcvd: 61


this not - any idea?

dig extraabi.de MX

; <<>> DiG 9.11.3-1ubuntu1.18-Ubuntu <<>> extraabi.de MX
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 62013
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;extraabi.de. IN MX

;; ANSWER SECTION:
extraabi.de. 59 IN MX 10 gw-test.mailkultur.de.

;; Query time: 0 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Fri Dec 09 12:21:51 CET 2022
;; MSG SIZE rcvd: 75

any idea?

thanks

 

[mathias1]

any idea?

 

[mathias1]

both hostname
gw-test.mailkultur.de and mail.extraabi.de point to 5.78.43.104

 

[Stoiko Ivanov]

this works:

dig extraabi.de MX

this not - any idea?

dig extraabi.de MX

those are the same commands - might be an issue with caching?

anyways - testing with extraabi.de from here I got quite changing results - did you change the entries recently?
(asked all 3 nameservers and got gw-test.mailkultur.de a few times and now getting mail.extraabi.de only...)

$ dig ns +short extraabi.de
robotns3.second-ns.com.
ns1.first-ns.de.
robotns2.second-ns.de.
$ dig +short +norec mx extraabi.de @robotns3.second-ns.com.
10 mail.extraabi.de.
$ dig +short +norec mx extraabi.de @robotns2.second-ns.de.
10 mail.extraabi.de.
$ dig +short +norec mx extraabi.de @ns1.first-ns.de.
10 mail.extraabi.de.
$ dig +short +norec mx extraabi.de @ns1.first-ns.de.
10 mail.extraabi.de.
$ dig +short +norec mx extraabi.de @robotns2.second-ns.de.
10 mail.extraabi.de.
$ dig +short +norec mx extraabi.de @robotns3.second-ns.com.
10 mail.extraabi.de.

In any case - both point to 5.78.43.104 - and this should work - the only thing I could imagine is that the sending servers refuse to send mail since the host uses gw-test.mailkultur.de in its smtp banner which does not match the hostname for connecting (mail.extraabi.de) - it's not the most common of configurations to refuse connecting to such hosts - but I can imagine some email-admins to have such an configuration

-> make sure that:
* your DNS entries are stable
* use the hostname of your MX as hostname of your PMG (this should make sure that the smtp-banner is correct
* ask the admins of the domains from which you do not receive e-mail what their logs say

 

[mathias1]

thanks. DNS entries are correct, I changed it to test PMG.
But it really seems that the mail admin of the sender domain has done some configrations that the mx must match to the receiver domain

 

[mathias1]

any idea how to use the gw-test.mailkultur.de fas mx for extraabi.de?