Email Reverse Proxy issue

[Maxim Dounin]

Hello!

On Sun, Jun 01, 2014 at 06:30:49AM -0400, omercz wrote:

> I am using Nginx as an Email reverse proxy.
> The email client sends a request to the nginx, the nginx fetch the WHOLE
> email(message) from exchange server, and only then manipulates it and sends
> it back to client.

This is not how nginx mail proxy works.

> Email Client<---->Nginx<----> Office 365
> 
> Everything is working great, besides the following problem, the Email client
> has a timeout of 30 seconds,
> but sometimes it can take the Nginx to download the whole email more the
> 30sec (if it has a big attachment).
> 
> My question is as follow:
> In the meantime can the nginx send 'something' to the client to keep him
> aware that something is being downloaded ? 
> Right now I have an ugly patch that sends on the open socket 'blanks' to the
> client every 20 seconds, until the nginx can send him the whole file.

After an authentication, nginx just establises opaque pipe between 
a client and a server.  Therefore, if the server sends anything, 
it will be immediately passed to the client.

-- 
Maxim Dounin
http://nginx.org/