Cannot find your hostname (in reply to RCPT TO command)

Hello,
sometimes i have messages from other email servers like this:

This is the mail system at host szpital.slupsk.pl.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

The mail system

<[email protected]>: host example.com[xxx.xxx.xxx.xxx] said: 550 5.7.1 Client
host rejected: cannot find your hostname (in reply to RCPT TO command)

I have DNS on other server than ISPConfig, I have SPF set.
Where find solution?

 

Have you set up reverse DNS PTR records for your mail server IP-address?
If szpital.slupsk.pl is the mail server hostname, and it advertises itself with that name when sending mail, you should have reverse DNS return that same hostname.

Code:

$ host szpital.slupsk.pl
szpital.slupsk.pl has address 213.25.19.141
szpital.slupsk.pl mail is handled by 0 szpital.slupsk.pl.

$ host 213.25.19.141
Host 141.19.25.213.in-addr.arpa. not found: 3(NXDOMAIN)

 

Yes i not have set DNS PTR record...

 

There is Tutorial:
https://www.howtoforge.com/tutorial...vice-with-ispconfig/#nbspreverse-name-service

 

Thanks!