Author: John W. Baxter Date: To: exim-users Subject: Re: [exim] 503 error Using Greylisting
On 9/26/07 2:36 AM, "James Isolder" <isolderj@???> wrote:
> I have recently added greylisting to my exim installation and now some of the
> mail servers that are connecting are giving me the following error.
>
> <<< 451 greylisted - try again later <user@???>... Deferred:
> 451 greylisted - try again later <<< 503 valid RCPT command must precede
> DATA <<< 451 greylisted - try again later <user@???>...
> Deferred: 451 greylisted - try again later <<< 503 Valid RCPT command
> must precede DATA Status: 4.3.0 Diagnostic-Code: SMTP; 451 greylisted -
> try again later.
>
> The email is then deferred and eventually bounced. Is there a easy way to
> avoid this problem while still greylisting.
Greylisting has to involve whitelisting broken servers you need to receive
mail from (and should involve whitelisting trusted servers--if a server is
known to pass greylisting and you want its mail, why insert delays?).
The 503 from Exim is required by RFC...the sending server should not be
sending DATA if all the recipients produced temporary errors. Turning off
pipelining can help.
