Question Undelivered Mail Returned to Sender gmail.com 550 5.7.1

[Pedro Magalhães]

Dear Sirs,

A few days ago, some messages sent to a mailbox with foward option return emails sended to domain gmail.com only.

The message invoke
"550-5.7.1 does not meet IPv6 sending guidelines regarding PTR records and
550-5.7.1 authentication. Please review 550-5.7.1"

The Sender domain only have IPV4 assigned
I try activate IPV6 on domain and create on DNS zone another PTR record with IPV6.

The problem occurs again.

Can you help me ?

Best Regards
Pedro Magalhães


Info:
OS ‪CentOS 6.6 (Final)‬
Plesk version 12.5.30 Update #45, last updated at Aug 30, 2016 03:16 AM
Email Service: Postfix 2.11.5-centos6.15081418

 

[Pedro Magalhães]

Dear Sirs,

A few days ago, some messages sent to a mailbox with foward option return emails sended to domain gmail.com only.

The message invoke
"550-5.7.1 does not meet IPv6 sending guidelines regarding PTR records and
550-5.7.1 authentication. Please review 550-5.7.1"

The Sender domain only have IPV4 assigned
I try activate IPV6 on domain and create on DNS zone another PTR record with IPV6.

The problem occurs again.

Can you help me ?

Best Regards
Pedro Magalhães


Info:
OS ‪CentOS 6.6 (Final)‬
Plesk version 12.5.30 Update #45, last updated at Aug 30, 2016 03:16 AM
Email Service: Postfix 2.11.5-centos6.15081418

 

[Lloyd_mcse]

Hi Pedro,
you need to ask your Server Provider to set the Reverse DNS (PTR) on your IPv4 and IPv6 address to match your server/postfix hostname.

<YOUR_IPv4> PTR mail.domain.tld
<YOUR_IPv6> PTR mail.domain.tld

Some providers allow you to set the PTR in their control panel, but you don't mention who you are with so I suggest you contact their support.
I hope that helps
Kind regards

Lloyd

 

[lvalics]

An another solution, in case if your ISP cannot provide IPv6 reverse DNS is to switch postfix to IPv4 only.
Change the following line in the postfix main.cf file and restart postfix:

inet_protocols=all

into

inet_protocols=ipv4