Re: [exim] Error message: Greylisted

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Author: John W. Baxter
Date:  
To: exim-users
Subject: Re: [exim] Error message: Greylisted
On 5/6/2005 10:48, "Akhthar Parvez. K" <akhthar@???> wrote:

> I saw some posts regarding Greylisting. But I could not see the exat one that
> I wanted.
>
> My problem is, I have got a bounced email with the following error message.
>
>  xyz@???
>     SMTP error from remote mailer after RCPT
> TO:<xyz@???>:
>     host mailserver[x.x.x.x]: 450
> <xyz@???>:
>     Recipient address rejected: Greylisted. Please Try Again Later:
>     retry timeout exceeded

>
> Could anyone tell me if this is caused due to the problem of my mailserver. Do
> I have to install Greylisting
> to fix this issue? If not, what is the solution for this issue.


Are you retrying at reasonable intervals for a new message with a temporary
failure? Greylisting implementations generally have a minimum retry window
(to get rid of spam engines which retry several times for a short time then
give up) and a maximum retry time (to reduce the number of false hits that
result from a different message from the same sender,recipient,IP).

I don't know of anyone doing greylisting with an initial waiting time longer
than 30 minutes (which is, after all, the SHOULD not retry until time in the
mail RFCs)(but I'm sure there are some)...I know of some that set that to
about 7 or 8 minutes. Four hours is fairly typical for the expiration limit
(but not set in stone).

You do need to check your Exim main log(s) (or appropriate substitute in
syslog's collection if you've set that up) for the message in question, and
see how often it was retried, and when.

Exim works well (for us) sending to sites with reasonable greylisting setups
(I haven't encountered a failure, but we might have them).

You could try sending to me at jwbaxter@??? (address ruined years
ago for spam reception...sigh!)

--John