c#: How does this work? -- c#

How does this work?

william
6/23/2006 10:36:12 PM

c#:

You guys are a great resource for learners such as I. I have seen the way
that you go over and above in explaining even the most mudane things to
beginners, and I think it is a great thing that you do here. I only hope
that you can help me understand how a certain type of application works.

I loaded an app that filters out spam (as it puts it) "before it hits your
inbox".

Now, how does this work? It changed my incoming and outgoing email servers
to 127.0.0.1. So, it appears that it is acting as a local proxy server.

But, how does it handle the email requests from my Outlook? Is there a
certain protocol that I could look at for Outlook or Thunderbird or Eudora?
If so, what would I be looking for?

I am curious because the application works quite well, but is restricted to
only a single email account (unless you pay a handsome sum) and I'd like to
write my own freeware version that is unrestricted in the number of accounts
that you can use.

I figure it will be a good project to learn .Net on, and it would be nice to
offer as freeware. Why freeware? Well, I'd like to see spammers hanging
dead in the streets...but the government kinds frowns on that. So, next
best thing is to smack a hot fire poker right in thier eyes by giving away a
tool that helps people never even see thier crap in the first place.

Any help you could give me towards learning what I need to know to write
this freeware .Net app would be greatly appreciated. I may even release the
source code under GPL (assuming my beginning code doesn't make me look like
too much of an idiot).

And please include your real name so that I can give proper credit in my
application's credit screen for your help.

Thanks!

Re: How does this work?

Göran_Andersson
6/24/2006 12:00:00 AM

Here's something to start unwinding information:

Mail is sent using the SMTP protocol, and recieved using the POP3
protocol. SMTP uses port 25 and POP3 uses port 110.

(There are of course other protocols in use, for an example if you
connect to an MS Exchange Server, but those are the ones that is
normally used.)

[quoted text, click to view]

Re: How does this work?

Tom Spink
6/24/2006 12:00:00 AM

[quoted text, click to view]

Hi William,

Take a look at http://en.wikipedia.org/wiki/Smtp
and http://en.wikipedia.org/wiki/Pop3

SMTP is the protocol used for sending e-mail, and POP3 is a protocol for
retrieving mail from a mail server. It looks like your application sits as
a man-in-the-middle between your client and your mail-server, i.e. when
Outlook wants to connect to the mail server, it actually connects to your
local computer, which simply forwards all the requests to the mail
server... which means you're totally right, it's acting as a local proxy
server.

Is there anything else specific you'd like to know?

Hope this helps,

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