[BlueOnyx:19147] Re: Solarspeed Email (off topic)

[Chris Gebhardt - VIRTBIZ Internet]

Hi Colin,

On 2/18/2016 9:19 AM, Colin Jack wrote:
> Deferred: 451 4.7.1 Greylisting in action, please come back later

That's the answer right there.  Give it 5-10 minutes and it should go 
through.

solarspeed.net is using greylisting, as indicated in the message.   The 
intended operation is for the message to sit in the sender's queue, then 
eventually re-send.

 From Solarspeed's package description:
Milter-Greylist delays acceptance of the first email from unknown 
senders for several minutes. After a waiting period the email is then 
accepted and the sender will be whitelisted for several days. While this 
is a really simple measure it catches about 80% of all SPAM. The simple 
reason for that is that most SPAM senders do not bother a second 
delivery attempt if the first attempt failed. A proper mailserver 
instead will always queue emails for multiple repeat delivery attempts.

More about greylisting:
https://en.wikipedia.org/wiki/Greylisting



-- 
Chris Gebhardt
VIRTBIZ Internet Services
Access, Web Hosting, Colocation, Dedicated
www.virtbiz.com | toll-free (866) 4 VIRTBIZ