Re: [exim] problem with mail getting rejected

On 2008-09-25 at 10:33 +0200, Ian Coetzee wrote:
> I have here a small but irritating problem.
>
> We carry a huge number of emails through or exim server (about 500
> user's worth).
>
> The problem is our ISP rejects our mails at 200 recipients/hour with a
> 554 error message, and that the exim then sends an mailer-deamon to
> the sender.
>
> Is there a way I can tell exim not to drop the mail, but keep resending it?

Downgrade 5xx to 4xx? No.

If your mail is legitimate, ask your ISP to raise the throttle limits
for your email. Any competent ISP will know that different customers
have different mail-sending behaviours and that some customers will
legitimately send more mail than any default cap picked to be
worthwhile. So just talk to them and discuss what an appropriate rate
limit is for your account.

If you just resend repeatedly then you hurt your chances of mail making
it out, as your connect rates go up.

If you rate-limit client-side then you won't know how long a given mail
will take to leave your realm of responsibility (unless you look) since
a few hours of high volume will delay mail until the evening. Since
this is presumably mail which people care about, being legitimate,
that's unlikely to be acceptable.

So, talk to the ISP. If you get nowhere with them and they list your
own IP space as dial-up/DSL/residential so you can't send email directly
without high probability of your mail being discarded, then you're in a
situation where you depend on being able to send X amount of mail
through your ISP and the ISP won't co-operate (or wants to charge an
amount of money that you're not willing to pay). At that point, you
search for a new ISP.

-Phil