Addressing the issue at hand, can you set your MTA not to offer STARTTLS 
command in the EHLO towards the TPG IP addresses, to force them to use the 
unencrypted channel?


Surely others who have played with their TLS1.2 settings on their MTA's are 
having this issue as well with TPG; how would they have gotten around it?


M.




________________________________
From: AusNOG <ausnog-boun...@lists.ausnog.net> on behalf of Bradley Silverman 
<bsilver...@staff.ventraip.com>
Sent: Monday, 23 July 2018 15:40
To: Mark Newton
Cc: ausnog@lists.ausnog.net
Subject: Re: [AusNOG] Issues receiving from TPG Mail servers.

@Michael - I agree that turning it off is the best way of solving it, the issue 
is we don't have the servers forcing TLS, that's TPG.

@Mark - These are shared hosting servers, think cPanel & Plesk. The one server 
is both mail, and website. Which means that the server has websites that accept 
credit card payments, and therefore is subject to PCI. Any system that is on 
that server is required to comply with PCI.

If the server was website only, then I'd agree 100% that it would be out of 
scope for PCI, but since the same server runs both email and websites for 
shared hosting customers, it is in scope.

We have zero issue with any other MTA, it is only these TPG MTA's that are 
forcing both TLSv1.0 and an old cipher. If they either turned off TLS or 
upgraded to TLSv1.2 they would be up to spec.

But we either have to make the decision to block TPG from being able to send to 
the 100,000s of email accounts we have, or make it so that none of our 
customers servers are PCI compliant. I'd rather speak to TPG and work with them 
to fix the underlying problem.

Regards,

Bradley Silverman | VentraIP Australia
Technical Operations

mobile. +61 418 641 103
phone. +61 3 9013 8464

On Mon, Jul 23, 2018 at 3:34 PM, Mark Newton 
<new...@atdot.dotat.org<mailto:new...@atdot.dotat.org>> wrote:
But PCI Compliance only applies to the Cardholder Data Environment.

Why on earth would you have a mail server in the Cardholder Data Environment?

And if it isn't in the CDE: You can run whatever version of TLS you want, and 
it's none of PCI's business.

  - mark



On Jul 23, 2018, at 3:06 PM, Bradley Silverman 
<bsilver...@staff.ventraip.com<mailto:bsilver...@staff.ventraip.com>> wrote:

Hi Matt,

Really appreciate you sending me that email, I will definitely send an email 
through to there!

@Mark Certainly not! PCI Compliance requires that TLSv1.0 be disabled on the 
server. Postifx/Exim/Dovecot are not exception to the rule, if we disable 
TLSv1.0 on the server and remove the weak cipher, then TPG's MTAs aren't able 
to send mail to us.

Regards,

Bradley Silverman | VentraIP Australia
Technical Operations

mobile. +61 418 641 103
phone. +61 3 9013 8464

On Mon, Jul 23, 2018 at 2:48 PM, Mark Newton 
<new...@atdot.dotat.org<mailto:new...@atdot.dotat.org>> wrote:
You're trying to exchange payment card information over email?

  - mark

On Jul 23, 2018, at 1:30 PM, Bradley Silverman 
<bsilver...@staff.ventraip.com<mailto:bsilver...@staff.ventraip.com>> wrote:

Does anyone have a contact at TPG regarding their mail servers?

We are having issues with their mail servers using non-PCI compliant ciphers 
which is stopping our servers accepting mail from them.


Regards,

Bradley Silverman | VentraIP Australia
Technical Operations

mobile. +61 418 641 103
phone. +61 3 9013 8464
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