Author: Exim Mailing List Date: To: exim-users Subject: Re: [exim] customizing 451 host lookup did not complete
On Sun, Feb 10, 2008 at 08:36:25PM +0100, Oliver von Bueren wrote: > WJCarpenter wrote:
> > Some MUAs are sloppy and don't tell me who the bad recipient is when
> > they get bad news after RCPT TO:. Thus, I don't know which of
> >
> For exactly that reason, I don't do any rejection at RCPT TO level for
> MUAs.
>
> To implement this, you best use SMTP authentication on a submission port
> for the MUAs and don't do any recipient verification during the SMTP
> transaction. The sending user will then get a bounce message in case of
> a wrong address, which lists the failed address in the message body.
> That works with any MUA.
Yep, what he said. Essentially, for MUA submissions, don't reject at ACL
time and instead let the routers generate a bounce instead.
The only thing I would recommend, though, is sender address
verification for MUA submissions from your local users. If it fails
verification, use the /no_details option on the verify ACL to ensure a
one-line response to the submitter. Outlook will tend to handle
one-line responses during MAIL FROM properly.
The main reason to verify the sender address is to ensure that a bounce
will get back to the sender properly. Users sometimes misspell the
From: header in their mail software, so rejecting immediately with
something like "YOUR EMAIL ADDRESS IS MISCONFIGURED" for local users
can be beneficial.
