The mailing list for listmasters using Sympa

[Adam Bernstein <address@concealed>]

> Hmm, I wonder if maybe we aren't doing VERP very well. The way you have
> it set up sounds a little different than what we have done.
>
> We've got verp_rate set to 10% in sympa.conf, and a generic bounce
> alias:

Yes, we're doing VERP in Postfix too, so it goes on everything, and even 
with the DKIM signing on everything too, we're still having no issues at 
all with load even during massive mailings to large lists.  Postfix seems 
very efficient at it, and in fact I believe we got deliverability benefits 
just from the fact that we were no longer doing SMTP batching; our deferral 
rates at Yahoo went down when we activated it.

It's very simple to set up -- we just modified the default sendmail_args in 
sympa.conf to add the "-XV" flag (for Postfix 2.3+), and in Postfix's 
main.cf added:

recipient_delimiter = +
propagate_unmatched_extensions = virtual

and I believe the Return-Path gets VERPed with the same format as Sympa 
would do (I've never quite made sure of this, but it can be customized if 
not).  We also have the bounce+ alias defined, so I believe we're getting 
all the benefits of Sympa's VERP processing even though it's actually 
Postfix generating it.

It's great that Sympa is adding these capabilities, but we are really 
liking the simplicity and elegance of having all low level sending-related 
functions handled at the lowest possible level, in the MTA.

     adam