ubuntu email piping as custom domain hosting

[9tontruck]

Hi,

I have a domain and DigitalOcean cloud ubuntu server, and I have been using the server as an email forwarding point. SImply, if someone sends an email to [e-mail], the server forwards to [e-mail]. The beauty of this is that I don't need to spend my server space used up for saving email and I can still use gmail UI. Downside is I have to reply using gmail account.

So I wanted to send an email using my domain email from gmail website. Custom domain email hosting in Google and Hotmail is not free so please don't mention it.

So I am looking for a way to smart email piping system and here is what it supposed to do:

customer -> server -> I
customer <- server <- I

**When customer sends an email**
from: [e-mail]
to: [e-mail]


**When server forwards to me**
from: [e-mail]
to: [e-mail]


**when I reply**
from: [e-mail]
to: [e-mail]


**When the server forward to the customer**
from: [e-mail]
to: [e-mail]

Basically it's free custom domain email hosting that allows using Gmail environment.

Is there any library doing this kind of things?

Thanks,