doesn't zip with greylisting

Vernon Schryver
Thu Dec 18 03:42:35 UTC 2003

> From: Tim Wicinski <>

> I've gotten two complaints today about servers getting a greylisting 
> embargo caused mail to be rejected.  Mine came from CUNYVM.CUNY.EDU

> ...
> I'm using the stock embargo time limits.

So regardless of greylisting, if someday your SMTP server were too
busy for more than 4.5 minutes, they'd give up?  That's lame.

Do they compound the error by trying a bunch of times within seconds,
as if a real 4yz problem might fix itself instantly?

> Gary Mills wrote:
> > I had a complaint that e-mail from users was no longer
> > working since I set up greylisting on our mail servers.  To confirm
> > this, I set up a free e-mail account on, and sent myself

> ...
> > Apparently,'s e-mail system treats this as a permanent
> > failure, and does not retry delivery.  I'm not impressed!

That's even worse for a product that is seems to have something to do
with security and archiving for legal requirements.

> > Are there any other mail systems that behave this way?  Is there
> > anything I can do in DCC to allow their mail to get through?  They
> > seem to use a bunch of outgoing SMTP servers.  I suppose that
> > greylist whitelisting by HELO or mail host are my only choices.

That's all I can see to do, modulo other headers you might expect
such an outfit to add.  Reducing the DCC greylist embargo duration
below the default sounds unlikely to help those determined to get 
RFC 821 and RFC 2821 wrong.

Vernon Schryver

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