On Tue, Jul 26, 2016 at 05:34:34PM -0700, Mike Kadin wrote:
> help.uber.com is a CNAME to frontends.uber.com which is a CNAME to
> frontends-sjc1.uber.com which has an MX record of mx.sendgrid.net.
> Sendgrid is our inbound SMTP provider:
> ...
> help.uber.com. 60 IN CNAME frontends.uber.com.
> frontends.uber.com. 60 IN CNAME frontends-sjc1.uber.com.
> frontends-sjc1.uber.com. 300 IN MX 0 mx.sendgrid.net.
> ```
> Delivery Host: mx.sendgrid.net
> Delivery IP: 167.89.125.4
> Size: 39.83 KB
> Result: 25: SMTP error from remote mail server after RCPT TO:<
> test123@???>: 454 4.7.1 <test123@???>: Relay
> access denied
> ```
Note that the DSN code is "4.7.1", which is:
https://tools.ietf.org/html/rfc3463
X.7.1 Delivery not authorized, message refused
The sender is not authorized to send to the destination. This
can be the result of per-host or per-recipient filtering. This
memo does not discuss the merits of any such filtering, but
provides a mechanism to report such. This is useful only as a
permanent error.
When I send a probe to <postmaster@???>, I get:
Reporting-MTA: dns; mournblade.imrryr.org
X-Postfix-Queue-ID: 23C8D284F25
X-Postfix-Sender: rfc822; exim-users@???
Arrival-Date: Wed, 27 Jul 2016 12:46:05 +0000 (UTC)
Final-Recipient: rfc822; postmaster@???
Original-Recipient: rfc822;postmaster@???
Action: deliverable
Status: 2.1.5
Remote-MTA: dns; mx.sendgrid.net
Diagnostic-Code: smtp; 250 2.1.5 Ok
So the issue sure looks like sendgrid is blocking the sending host,
envelope sender domain, or specific recipient address.
--
Viktor.
