[BlueOnyx:21591] Re: 550-5.7.1 this message does not meet IPv6 sending guidelines regarding PTR

[Michael Stauber]

Hi Lewis,

> On a 5209R box providing email connected to Insight/Spectrum cable ISP
> I'm getting complaints of the following error:
> 
>> The original message was received at Wed, 20 Dec 2017 09:37:36 -0500
>> from rrcs-96-11-138-58.central.biz.rr.com [96.11.xx.xx]

This isn't the server IP, right? It's your home or office IP where you
connected to your server to send the email, correct?

In that case please do this:

Go to "Server Management" / "Network Services" / "Email" and in the
"Advanced" tab tick the checkbox "Hide Previous Headers" and save the
changes.

That will make sure that your home IP won't show up in headers of emails
sent through your server.


> A quick Google shows this may be a problem for at least the last two years:
> 
> http://forums.businesshelp.comcast.com/t5/IPV6/Google-mail-requires-IPv6-PTR-record-but-Comcast-does-not-supply/td-p/27056
> 
> Is this fix, disabling IPV6 in postfix, applicable to 5209R?

BlueOnyx uses Sendmail and not Postfix. Furthermore: It is already
configured to only use IPv4. I noticed this during the IPv6 (and
IPv4+IPv6 dual stack) development of BlueOnyx that I'm currently working
on. As is our Sendmail can only "talk" to MTA's that either run on IPv4
themselves, or can talk via IPv4 to MTA's that use dual stack. That also
means that you don't need any AAAA records or an IPv6 PTR for your
BlueOnyx yet, because you're not (yet) using IPv6 on it.

This is rather a false alarm of the receiving MTA, because it triggers
on your IPv6 home IP and not the IPv4 IP of your BlueOnyx. Suppressing
the previous headers on your BlueOnyx helps you to get around this.

-- 
With best regards

Michael Stauber