SMTP server w/o using Twisted framework

[_spitFIRE]

On Jul 5, 1:34 pm, "Jeff McNeil" <j... at jmcneil.net> wrote:
> If you just want to send mail, you should be able to use the standard
> smtplib module (http://docs.python.org/lib/module-smtplib.html). If
> your recipients are on the Internet, you would need to handle MX
> resolution yourself.
>

How complicated is to handle the MX resolution by myself? I'm sorry
that I don't have a clue regarding that. Any pointers would be greatly
appreciated.

> I know you said you want to avoid a relay server, but it's probably
> the best bet unless you control the SMTP infrastructure or are simply
> sending messages locally.

The problem is that with the scenario I'm faced with, I don't have any
reliable SMTP server that I can use. Hence, I though I will spawn my
own light-weight SMTP server that can send mails to the people I want,
on the Internet. But, from what you are saying it seems, it might not
be that light weight after all!

> Otherwise, you'll probably need to also
> implement queuing and retry logic (depending on your requirements).

Isn't there a library module that can help me implement all this?

> There are also some warning lights that may go off and flag your mail
> as spam if you're using a method like that...
>
> -Jeff

Would you please fill me in with some pointers as to why my mail might
get flagged as spam? Would it be considered spam even if I've a valid
from address, and a proper message/subject? Does the spam filter also
rely on the sending server's DNS etc because of which you say it might
get flagged as spam?