Wietse Venema:
> Quanah Gibson-Mount:
> > We recently deployed into AWS, and were following
> > <https://www.agari.com/scaling-postfix-on-aws-with-elastic-load-balancing/>.
> >
> > However, we found that if we set postscreen_upstream_proxy_protocol=haproxy
> > we are then no longer able to connect directly to the MTAs to send mail.
>
> Unlike XCLIENT, which sends information AFTER the SMTP handshake,
> HaProxy cannot be used in mixed mode, because it sends information
> BEFORE the SMTP handshake.
>
> How would Postfix know that the client wants to send HaProxy
> information before the SMTP handshake? If it could predict the
> future, then I would be rich.
>
> > Is there any ability to support a mixed mode, where some clients are coming
> > in via an upstream proxy and some are not?
I suppose that one could configure a namaddr_list (and use IP address
patterns only) that skips the haproxy protocol handshake.
Wietse
