Request for some smtp example with and without auth

[Anton Yuzhaninov]

Atif Ghaffar wrote:
> If I correctly undrestood,
> 
> 1. nginx as smtp proxy is useful when using smtp auth. (to dispatch to 
> different backends)

IMHO nginx as smtp proxy with auth useful only to reuse auth server created for pop/imap proxy.

For pop3/imap nginx need for proxing different users to different backend (where mail stored).
In smtp message can be send via random server.

nginx can be used for load balancing between different servers with MTA, but for load-balancing 
only better to use something like IPVS (in Linux) or pf (in BSD).

> 2. nginx as smtp proxy is useful when not using smtp auth. (to do ip 
> based checks)

Without auth (incoming mail) nginx can be used to save resources if only ip not in RBL proxied 
to servers with MTA.

But I don't know is current nginx version used anywhere in production as smtp proxy without 
auth. IMHO it not ready for production, because of lack smtp pipelining support. Some MTA 
(probably some sendmail versions/configs) have bad habit to use pipelining even if it support 
not adversed in EHLO reply.

-- 
  Anton Yuzhaninov