Author: Exim Mailing List Date: To: exim-users Subject: Re: [exim] Callout verification for forwarding addresses?
On Sat, Sep 29, 2007 at 02:07:11PM +0200, elvis_the_king@??? wrote:
> We have quite a lot of addresses that forward mail to dozens of recipients. Unfortunately it happens quite often that the servers for addresses we forward to reject the mail for some reason.
>
> It would be nice if one could, after the DATA has been given on the incoming connection, try to forward the mail to the downstream servers and answer the DATA command with the result we got ourselves.
>
> However I doubt this is possible, especially if forwarding to more than one address? How to handle different results (one downstream server accepts, one rejects) in this case?
>
> A simple recipient callout does not suffice if the address we forward to is valid but the server rejects the mail based on content.
>
> Thanks for sharing your thoughts :)
Hmm, well, my opinion is that callouts should only be made to other
mail systems that you or your company owns. If you will be doing
callouts to other mail servers, you should limit it only to systems
that you have a prior agreement with and that have added you to their
whitelists.
Doing callouts without prior permission is a good way to land yourself
in a permanent blackhole list. In the end, they don't gain you much
anyway, especially if you configure a separate instance of Exim to
handle bounce messages and messages that cannot be immediately
delivered for some reason.
I know others will immediately disagree with me, but you gave us prior
permission to share our thoughts... ;)
