Issue Mail to some addresses not sent - Postfix - Connection refused

[tetrahall]

Hello,
I am having this strange problem. Emails can be sent to some addresses but not others.

OS: CentOS Linux 7.6.1810 (Core)
Product: Plesk Onyx 17.8.11 Update #95

/var/log/maillog says this:-
Mar 21 17:13:54 server416 postfix/pipe[1981]: BD72B21DB1: to=<user@domain.com>, relay=spamassassin, delay=8.1, delays=0.17/0.01/0/7.9, dsn=2.0.0, status=sent (delivered via spamassassin service)

Mar 21 17:13:54 server416 postfix/qmgr[438]: BD72B21DB1: removed

Mar 21 17:13:54 server416 postfix/smtp[2007]: connect to domain.com[xx.xx.xxx.xxx]:25: Connection refused

Mar 21 17:13:54 server416 postfix/smtp[2007]: C5D5F2207C: to=<user@domain.com>, relay=none, delay=0.11, delays=0.01/0.02/0.09/0, dsn=4.4.1, status=deferred (connect to domain.com[xx.xx.xxx.xxx]:25: Connection refused)

I have tried these (to no avail):-

1. added the IP address to WHITE LIST in Server-Wide Mail Settings
2. Disabled Spamassassin
3. Re-started POSTFIX

Is there something I can disable/enable to get the mail through?

Please help. Thanks

 

[Kaspar]

Is port 25 open and can you connect via telnet to port 25 to your server ?

 

[tetrahall]

Not sure about their end really. It's not always possible to find this out.
But If I telnet their IP address, I get the same result .. (Connection refused)

Is there a simple test to find out from my end whether their port 25 is open?
If not, is there a way round it?

 

[Kaspar]

Sorry, I meant to ask if port 25 is open on your server? Can you connect to your server from your local computer?

Also, it might be worth checking if your server is perhaps blacklisted.

 

[tetrahall]

Thank you for the feedback. Port 25 is open on my server and I can connect to the server from my local computer.

I checked our server (domain) and it is 100% not blacklisted. I used this link:-

MultiRBL.valli.org - Blacklist, Whitelist and FCrDNS check tool

Free multiple DNSBL/RBL lookup and FCrDNS check tool. Test the IP (IPv4 or IPv6) of your mailserver on more than 200 blacklists and whitelists.

multirbl.valli.org

It's one of those things that bug ! One tried every possible option only to end up with "Connection refused" !

 

[Bitpalast]

While multirbl is a great place to check your ip for blacklisting, it is still thinkable, that the specific server of your mail recipient does not want to talk to your server. They might have their own solution to fight spam. Would it be an option to ask the recipient why his server does not allow connections?

 

[tetrahall]

Thank you Peter. If the recipient server didn't want to talk to the sending server, the sender would usually receive a "rejection" message of some sort. But your suggestion is still a possibility.

 

[weltonw]

Is outgoing 25 allowed? That's really what's important here.

Try something like

telnet aspmx.l.google.com 25

You should get back

Connected to aspmx.l.google.com.
Escape character is '^]'.
220 mx.google.com ESMTP i13si11298368ilm.161 - gsmtp

 

[tetrahall]

Thank you John. Yes, I get the expected result back.

 

[weltonw]

Sounds like their issue then. I'd contact the mail provider.

 

[tetrahall]

that looks like the only option left!
Thank you ALL for your responses.

 

[StormFiber]

Hello,
I am having this strange problem. Emails can be sent to uae escorts some addresses but not others.

OS: CentOS Linux 7.6.1810 (Core)
Product: Plesk Onyx 17.8.11 Update #95

/var/log/maillog says this:-
Mar 21 17:13:54 server416 postfix/pipe[1981]: BD72B21DB1: to=<user@domain.com>, relay=spamassassin, delay=8.1, delays=0.17/0.01/0/7.9, dsn=2.0.0, status=sent (delivered via spamassassin service)

Mar 21 17:13:54 server416 postfix/qmgr[438]: BD72B21DB1: removed

Mar 21 17:13:54 server416 postfix/smtp[2007]: connect to domain.com[xx.xx.xxx.xxx]:25: Connection refused

Mar 21 17:13:54 server416 postfix/smtp[2007]: C5D5F2207C: to=<user@domain.com>, relay=none, delay=0.11, delays=0.01/0.02/0.09/0, dsn=4.4.1, status=deferred (connect to domain.com[xx.xx.xxx.xxx]:25: Connection refused)

I have tried these (to no avail):-

1. added the IP address to WHITE LIST in Server-Wide Mail Settings
2. Disabled Spamassassin
3. Re-started POSTFIX

Is there something I can disable/enable to get the mail through?

Please help. Thanks

Hey Peter is saying perfectly: "While multirbl is a great place to check your ip for blacklisting, it is still thinkable, that the specific server of your mail recipient does not want to talk to your server. They might have their own solution to fight spam. Would it be an option to ask the recipient why his server does not allow connections?"

 

[tetrahall]

Thank you, StormFiber. Agreed. But that option may not be always possible. For example, a certain IP address leads to "Connection Refused". I cannot contact the sender neither via email nor phone, to ask them to inquire.

I am left then with looking up the IP address source, only to find this: "REDACTED FOR PRIVACY". I am only left with the webhost or the domain holder. I try to contact them, to no avail. Then I give it up.

One possibility of this "Connection Refused", I think, is a case like this. The sender has not configured their name servers. I am not sure about this to be honest.

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