Re: [nznog] Xtra mail admin and ptr records...

On 11/09/13 09:31, Joe Abley wrote:

On 2013-09-10, at 17:25, Mark Foster wrote:

...

Um.. Don.. so you're saying that because you've implemented a policy that rejects email based on the contents of the PTR, that this is Telecom's fault and they need to 'fix' it? It's not an uncommon policy. People even tried to document it in the IETF, although they didn't get very far (I think the idea is too ugly to imagine hanging it on the otherwise pristine walls of the ivory tower).

Drawing Xtra's attention to it does not seem like a bad thing. Using NZNOG as the primary way to contact Xtra mail admins seems a bit unfortunate, especially if it's necessary :-)

Hi Joe, and others - I've come across it before, and if IETF had moved on it and saw widespread adoption as a result, perhaps it'd work. However without ratification, any measure like this is a cost:benefit analysis and requires the person implementing the policy to decide if the cost is worth it, including as necessary, negotiating with remote mail admins and attempting to convince them that their arrangements aren't 'correct enough'. Or creating the means to whitelist particular senders. The people who run the nzvanlines.co.nz mail platform are the only people who need to care on this; they can request a DNS change from Telecom/Xtra or they can switch to Xtra's 'smarthost'. Or Don can choose not to use this particular policy, or they can whitelist this particular domain or IP address. I don't see Telecom setting up custom PTR's by default; they've created a matching forward/reverse pair and anything other than that would seem to be their customers concern. This is not a 'fault' and nor does it need to be 'fixed'; it's a combination of decisions made by the two mail server admins and if they create a conflict, it's up to them to sort it out. A broadcast on NZNOG asking for the ISP of one party to step in and make arbitrary changes to meet the requirements of one side of the conflict, would seem inappropriate.

From where I sit, it's not Telecom's problem until Telecom's own customer approach them about it.

Mark.