Re: Validating MTA-STS setup, by writing to improperly configured MTA-STS sites

Could you simulate this by having your outbound not attempt STARTTLS (perhaps just to a specific host)? If your MTA code understands the difference between not-offered and not-attempted, that wouldn't work.  Just a thought.

--
Alex Brotman
Sr. Engineer, Anti-Abuse & Messaging Policy
Comcast

> -----Original Message-----
> From: ietf-smtp <[email protected]> On Behalf Of ????? ????????
> Sent: Monday, January 10, 2022 11:53 AM
> To: [email protected]
> Subject: [ietf-smtp] Validating MTA-STS setup, by writing to improperly
> configured MTA-STS sites
>
> Hello,
>
> I want to validate, that outgoing MTA-STS does work correctly.  I want to
> send an email to a site, which has broken MTA-STS, and see what happens.
>
> Can somebody name a sample site, which (on purpose, for testing purposes,
> unintentionally for the moment) announces MTA-STS, but does not offer
> STARTTLS?
>
> I found only
> https://urldefense.com/v3/__https://mtasts.xyz/__;!!CQl3mcHX2A!TTR4o6
> 1qatE9S6m9-9E3V266j07tny3GsF_Gb-Cme7r-
> bqM2EnnrsBWVuvBYC0D3pGbE_raAtg$  trying to perform outbound tests,
> but its MTA-STA setup is too broken - the certificates are outdated and the
> HTTP-policy is thus ignored.
>
> Greetings
>   Дилян
>
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