I don’t think my question was well understood. We are looking to implement Exim as a scalable cloud-based MTA, but without egress access to the internet. Exim’s feature set and performance are excellent for this, but the lack of SOCKS support prevents us from implementing it. I don’t think HAProxy can provide egress SOCKS support.
Please excuse my poor ASCII diagram.
+---------------+
|SMTP (internal)|
+------+--------+
|
+------+--------+
| (internal) |
| Load Balancer |
| |
+---------------+
+-------+---------------+---+
| | |
| | |
+----+----+ +-----+---+ +----+----+
|Exim Node| |Exim Node| |Exim Node| ... -> Scale to infinity (internal)
+---+-----+ +----+----+ +----+----+
| | |
| | |
+---v--------------v-------------v-----+
| |
| Socks 4/5 Devices |
| (external) |
+-------------------+------------------+
|
|
+------------------+-------------------------+
| |
| Internet/TCP/IP (MX routing out SOCKS) |
| |
+--------------------------------------------+
From: Eugene Istomin [
mailto:E.Istomin@edss.ee]
Sent: Tuesday, February 10, 2015 3:03 AM
To: exim-dev@???
Cc: Schlosser, Matthew (TR Technology)
Subject: Re: [exim-dev] EXPERIMENTAL_PROXY clarification
Matthew,
this is protocol made by Willy Tarreau - "The PROXY protocol provides a convenient way to safely transport connection information"
So, Haproxy as frontend, exim as backend (we are using exim as localhost:25 listener)
---
Best regards,
Eugene Istomin
On Friday, February 06, 2015 11:34:28 PM matthew.schlosser@???<
mailto:matthew.schlosser@thomsonreuters.com> wrote:
> I'm reviewing the EXPERIMENTAL_PROXY documentation and it looks like this
> allows me to use Exim as a proxy.
>
> Is there any way to do the inverse? I'm thinking a transport option to send
> via a socks proxy. The idea is to use Exim MTA inside an environment with
> no default route to the internet.
>
> Along the lines of:
>
> begin transports
> proxy_smtp:
> driver = smtp
> proxy = <socks4|5>:<proxy host or ip>:<port> (or equivalent lookup)
>
> Matthew Schlosser
