Resolved IONOS NOT ACCEPTING INCOMING MAIL FROM PLESK - 554 BAD DNS PTR RESOURCE RECORD

[falconsi]

Server operating system version

Ubuntu 22.04.2 LTS (Linux container in Proxmox in a Dedicated Root Server in Hetzner - OPNSense Router)

Plesk version and microupdate number

Plesk Obsidian v18.0.52_build1800230516.12 os_Ubuntu 22.04

Hello all!

I purchased a Plesk license after making a few tests in trial. I configured a domain in Ionos, changed nameservers to point to Plesk and everything is working perfectly (DNS prop is 100%).
My problem is, when I send emails (from [email protected]) to Ionos customers, they get bounced with following error:

<[email protected]>: host mx00.ionos.es[212.227.15.41] refused to talk

to me: 554-kundenserver.de (mxeue010) Nemesis ESMTP Service not available

554-No SMTP service 554-Bad DNS PTR resource record. 554 For explanation

visit SMTP Error Messages of the IONOS Mail Servers - IONOS Help

At the moment, I checked sending to Gmail, Yahoo, Microsoft (@msn.com, @outlook.com, @live.es) and they work perfectly, problem is only with Ionos.

I visited SMTP Error Messages of the IONOS Mail Servers - IONOS Help to see how to solve it, and it says:

554 Bad DNS PTR resource record​

Problem:

Email from your email server has been rejected because the PTR resource record (PTR-RR) of your IP address does not comply with IONOS policy.

Solution:

Switch from a dynamically assigned IP address to a fixed IP address.

Verify that the PTR-RR is the default generic entry of your provider. Assign your email server its own full domain name (FQDN).

So, I've already have a fixed IP address. My server is in a dedicated root server in Hetzner, virtualized in a Linux Container in Proxmox. I made this in Robot:



Waited for changes to propagate (in dnschecker.org), but still getting same error from Ionos.

Tried to add a PTR record in Plesk like this:



But I get this error:



Also tried with /32, got the same error.

Also changed spf to this (as seen on another post):



But doesn't work either.


This is all I could try with my (limited) knowledge, would you help me sorting this out?


Thanks in advance.

 

[falconsi]

Also changed HELO in postfix's main.cf to pejeverdeftv.es and passed all tests in Spam Test Result, but still not able to send to ionos.

 

[falconsi]

Ok, now I found this for the PTR record problem

https://support.plesk.com/hc/en-us/articles/12377241566615-Unable-to-add-PTR-record-Incorrect-DNS-Record-parameter-values-were-specified

And was able to add it. Let's wait to see if it works

 

[Peter Debik]

What does the Yes/No radio button do? Could it be possible that Reverse DNS has been configured, but has not been turned on at your data center?

 

[MarkM]

# host 88.198.98.121
121.98.198.88.in-addr.arpa domain name pointer pejeverdeftv.es.

PTR seems fine currently.

Is mail going out to ANYONE at all?

 

[falconsi]

What does the Yes/No radio button do? Could it be possible that Reverse DNS has been configured, but has not been turned on at your data center?

It's in the alt text, hehe. Yes/No enables/disables traffic alerts. So no, not needed for reverse DNS

 

[falconsi]

# host 88.198.98.121
121.98.198.88.in-addr.arpa domain name pointer pejeverdeftv.es.

PTR seems fine currently.

Is mail going out to ANYONE at all?

At the moment, I checked sending to Gmail, Yahoo, Microsoft (@msn.com, @outlook.com, @live.es) and they work perfectly, problem is only with Ionos.

As said in the OP, yes, It was going out everywhere I tested but Ionos.
Anyway, right now it works perfectly. Maybe the problem was the PTR not fully propagated.

Thanks everyone. Have a good one.