Re: [exim] Using verify sender

On Mon, 2011-05-23 at 13:13 +0100, Graham Butler wrote:
> Is the use of 'verify sender' recommended, and can anybody who has included 'verify sender' give any feed back on any problems they have experienced regarding rejections of legitimate emails.

We've had it switched on here (Loughborough) for as long as I can
recall, right back to the equivalent test in Exim 3.x days.

All it does is ensures the sender domain exists, and resolves correctly.
If it does not, you have no way to return mail to the domain, and
therefore probably don't want the inbound message.

It is of course entirely plausible that transient DNS failures can cause
this to reject entirely legitimate mail, but if these DNS failures are
local to you that's the least of your worries.

You could obviously switch it on using the "warn" verb (as opposed to
"deny") and log anything it finds, then you'll have an idea if it's
going to cause a problem.

Graeme