sahostking

Well-Known Member
May 15, 2012
401
28
78
Cape Town, South Africa
cPanel Access Level
Root Administrator
Twitter
We currently use Mailscanner and currently have it setup well we believe and its blocking quite a bit of spam but we are noticing a heavy increase in spam hitting our servers now. However I used to work for a company that used greylisting. It had some issues but they tweaked it quite well.

I am wondering if other hosts are using it and if it is working well for them as I've heard of Greylisting deferring PHP email sends from other servers and then blocking and some customers then loosing legitimate emails is this still the case or is it far better than before now as spam seems to be quite on the rise again.
 

cPanelLauren

Product Owner II
Staff member
Nov 14, 2017
13,274
1,285
313
Houston
I believe it's useful to understand how greylisting works. OUr configuration is discussed here Greylisting | cPanel & WHM Documentation

Importantly, greylisted items are deferred for a specific amount of time dependent on the amount of times they've sent or resent mail.

Attempts​
First resend attempt​
Greylisting’s response​
One​
N/A​
  • Defer email back to sender.
  • Add triplet to the Greylisting database.
Multiple​
Within 10 minutes of initial email.​
Continue to defer email back to sender until the Initial Deferral Time expires.​
Multiple​
10+ minutes after initial email.​
  • Deliver email to recipient.
  • Continue to deliver email from this triplet until the Record Expiration Time expires.
Multiple​
240+ minutes after initial email.​
Treat email as if a new, unknown triplet sent it.​


The point at which you could potentially lose mail would be if they sent the first email and did not automatically retry when the initial mail was deferred.