I believe you are trying to use the same IP address for the 3 exim
instances, otherwise the solution would be quite simple binding each
instance to the proper IP address. Right? Or do you have 3 different
public IP addresses?
If you have only 1 public IP, does a solution forwarding to a subdomain
via system_aliases+dsearch+local_parts+cron job updating user list,
would satisfy?
example:
adam@??? -> adam@???
eve@??? -> eve@???
keyser@??? -> keyser@???
soze@??? -> soze@???
contact@??? -> contact@???
--
On 2023-04-15 11:53, Sebastian Arcus via Exim-users wrote:
> I have a number of Exim servers behind a NAT gateway (actually
> connected with vpn's to a cloud vps - but I'm hoping this is not
> relevant to this post). I would like the gateway to send incoming port
> 25 traffic to the correct Exim server based on SNI in incoming TLS
> packets - as different Exim instances serve different email domains.
> The setup would look like this:
>
> [Internet]
> |
> |
> (smtp port 25)
> |
> v
> |
> [Cloud server]
> |
> v
> |
> ----------------------------------------
> | | |
> | | |
> [Exim server 1] [Exim server 2] [Exim server 3]
>
>
> I would have preferred to do this at IP tables level - but apparently
> not really possible. It seems the next option would be HAProxy. Has
> anyone here used HAProxy or run a setup as above, or know if this is
> actually doable? Any suggestions much appreciated.