Reverse DNS does not match SMTP Banner

[Chrisa]

Problem:
"Reverse DNS does not match SMTP Banner" as reported by http://mxtoolbox.com
And in a telnet test, EHLO returns a "250-server-name" instead of the domain name

(email is working including to microsoft, this is more of a ranking/reliability issue)

Setup: VPS with a single IP address with multiple domain names, each with email.

Details:
Postfix mail server
Plesk 12.5.30
OS Ubuntu 14.04.4 LTS (64bits)

Additional Info:

telnet mail.domain.tld 25
EHLO mail.domain.tld
250-vps-server-name-instead-of-domain-name
250-PIPELINING
250-SIZE 10240000
250-ETRN
250-STARTTLS
250-AUTH DIGEST-MD5 CRAM-MD5 PLAIN LOGIN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN

/etc/postfix/main.cf
contains
myhostname = vps-server-name
I Tried #commenting it out and restarting postfix, n/c

I have one of the domains setup as the reverse DNS for the VPS.
Testing was done with that domain but results are the same for all domains

I've reviewed the existing discussions with the same symptom but was not able to find a solution in any of them.

Thanks

 

[Lloyd_mcse]

Hi Chrisa,
You will need to speak to your hosting provider to get them to set the PTR (or Reverse DNS) for your IP address to match your server name...

eg: mail.domain.tld

Though some providers allow you to set the PTR yourself.

Regards

Lloyd

 

[Chrisa]

Hi Lloyd,
I do have control over the dns settings, there is already a PTR record, this is the default setting:
X.X.X.X / 24 PTR domain.tld.

Is that correct?

NOTE: I did try changing this on one domain but no success
X.X.X.X / 24 PTR mail.domain.tld.

Thanks
Chris

 

[Lloyd_mcse]

Hi Chris,
Are you referring to the PTR in Plesk's DNS settings? This is not the same as the PTR for the IP address as this resides with the administrator of the IP block, though like I say some providers do allow user set PTR/rDNS through their control panels, who provides your VPS?
Regards

Lloyd

 

[Chrisa]

Hi Lloyd,
The VPS is through ovh.com. There is a setting in their control panel for a single reverse dns ip/domain name association per VPS but there doesn't appear to be any method to add PTR records for each domain in the VPS.


Thanks
Chris

 

[Lloyd_mcse]

Hi Lloyd,
The VPS is through ovh.com. There is a setting in their control panel for a single reverse dns ip/domain name association per VPS but there doesn't appear to be any method to add PTR records for each domain in the VPS.

Hi Chris,
yeah that's right, you can only set one rDNS/PTR per IP address, so I suggest you chose a domain to use and use that with your hostname, mailname and "myhostname" in Postfix (and update the hosts file).
And it's better to use mail.domain.tld rather than just domain.tld as the PTR.

Anyway as long as the PTR at OVH is set to the same as the Postfix myhostname you should be fine.

Regards

Lloyd

 

[Chrisa]

Hi Lloyd,

Thanks. The result actually surprised me. Now all domains on this VPS are passing this test even though another domain is in the record:

domaina = domain set in rDNS of VPS and "myhostname" in /etc/postfix/main.cf
domainb = just another domain in the same VPS

telnet mail.domainb.tld 25
EHLO mail.domainb.tld
250-domaina.tld

NOTE: This works on domains that have had the Plesk PTR record modified to include mail.domain.tld. and well as domains at the default PTR setting of domain.tld.

Thanks again
Chris

 

[Lloyd_mcse]

Yeah that's right, as long as the Postfix myhostname matches the PTR the other domains will also be fine
Glad I could help
Regards

Lloyd

 

[fmaz008]

Hi Lloyd,
The VPS is through ovh.com. There is a setting in their control panel for a single reverse dns ip/domain name association per VPS but there doesn't appear to be any method to add PTR records for each domain in the VPS.


Thanks
Chris

Hi Chris,

I know this has been a few years but I just found your post.
I to have a VPS with OVH as well and I have been facing the same issue than you have.
Where did you find the setting in the control panel to add a reverse DNS ip ?
Are you talking about the OVH Cloud panel or the Plesk panel for the VPS itself ?

Thank you !