- 550 error for ipv6/PTR ?

Jimmy Hess mysidia at
Wed Jan 15 22:18:25 UTC 2014

On Wed, Jan 15, 2014 at 12:05 PM, Darren Pilgrim <nanog at> wrote:

> host[2607:f8b0:4002:c01::1a] said: 550-5.7.1
> [2607:fc50:1000:1f00::2      16] Our system has detected that this
> 550-5.7.1 message does not meet IPv6 sending guidelines...

I could not reproduce the error during a telnet test.
However, I see a substantial number of outgoing  550 5.7.1  rejects  that
look just like that,  mixed in with accepted mail to
So it would appear to be transient, but ongoing.

And more than a bit troublesome, since it is shown as a 550 reject,  and
delivery therefore will not be deferred and retried appropriately.

Jan 15 15:41:29  [...] Failed "Site (2607:f8b0:4002:c01::1a) said
after data sent: 550 5.7.1 more information. q48si1281225yhb.127 - gsmtp
550-5.7.1 [2607:f360:0:1f0::40:2f00      12] Our system has detected that


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