SMTP can handle single or multi connection email sending request. SMTP relay fill forward to destination of email sender. Some attachment can put on email and require to scan before sending to public network. this a may have some unwanted files or executable that may danger to everyone recieved this email. this attachment may have some compressed file that may to extract and check before sending. This file probably may have DRM it before send

Project Proposal

1. High-level project introduction and performance expectation

Email scanned with destination listed, brute force attack, 

If possible, smtp server can handle multi devices and can send to local (when offline) or send to foreign smtp when interlocal (other houses/other email site). the database is for local delivery is small for offline/no electricity saving

2. Block Diagram

[Home Device/Office Device] <--> [Home/Office Smtp Mail server]   <--> Internet <--> Mail 

3. Expected sustainability results, projected resource savings

the expected (if possible) use small power.

The smtp server can handle online request from small device with saving data mail when offline. and send to other when online. 

The smtp project is possible if tcp/ip stack is available and ethernet is available and working good