Chip wrote:
> First, do the users of VERP experience greater deliverable rates
> compared to those senders who forgo VERP?
VERP will not directly improve deliverability.
It will allow you to more quickly and accurately identify addresses that
are not deliverable, and remove them from future mailings, so indirectly
it will increase the percentage of messages that are deliverable by
removing no hopers.
However this comes at a cost of requiring a single delivery per
recipient (which you may already require if you do any message
personalisation or tracking).
> It would be great to know if
> implementing it in addition to other best-practices helps in deliverable
> rates. (In our setup the Mail User Agent can only create VERP headers
> when using phpmailer and not SMTP, and therefore an unsubscribe link in
> the headers cannot be created, perhaps adding to lower deliverablity rates?)
>
> Secondly, would we be better of getting Exim to produce the VERP
> error-to headers rather than our Mail User Agent -- would doing so cut
> down on overhead and processing memory?
I can't comment on the deliverable rates - it sounds like you are
working in a marketing type application, which is not where my
experience lies.
You can do VERP at either MUA or MTA level (although the MTA has to be
at least partially aware of VERP to allow capturing of any bounce
messages). It sounds like you have some reasons to do this within the
MTA due to your MUA functionality. That should work fine. In general
handling VERP in the MUA allows more flexibility in things such as
deliverability tracking (against, say, message content). However this
is unlikely to be a major difference.
The exim mailing list does VERP at the list processing level rather than
within the MTA - this allows us to use VERP for some, but not all,
deliveries, which is a bandwidth compromise that works for us.
Nigel.
--
[ Nigel Metheringham ------------------------------ nigel@??? ]
[ Ellipsis Intangible Technologies ]
