How does this work?

[william]

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!

 

[Göran Andersson]

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.)

 

[Tom Spink]

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!

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,
-- Tom Spink

 

[Mehdi]

[FU2 microsoft.public.dotnet.general]

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?

In addition to the other answers, you should also have a look at the IMAP4
protocol (often used for corporate email systems). The free version of
hotmail uses its own and not documented protocol.

By the way, there are free anti-spam systems that can deal with multiple
accounts. Have a look at Spam Bayes <http://spambayes.sourceforge.net/>. It
free, open source and works either as an outlook plugin (outlook only) or
as a local proxy server (similar to what you've descibed, works with any
email client). I've tried to outlook plugin and, once it's been trained,
i've found it to be very effective.

PS: praising the participants of this newsgroup for how great what they're
doing is does not frees you from respecting the basic usenet posting rules.
In particular, it is generally considered very bad manner to cross post
accros multiple groups. In the very rare cases when your post doesn't fit
in any group in particular, cross-posting to 2 different groups or at the
very most 3 groups is tolerated but in this case you should set the
Folloup-To field to one group only and specify in your post in which group
the discussion is going to take place. Followup set to
microsoft.public.dotnet.general.

 

[william]

Thanks Göran! That's just they type of stuff I need to know.

I will begin my project today and should have a beta ready by Monday.

 

[Oenone]

I loaded an app that filters out spam (as it puts it) "before it hits
your inbox". [...]
I figure it will be a good project to learn .Net on, and it would be
nice to offer as freeware.

Not wanting to stop you working on your project, but you do know about
POPFile?

http://popfile.sourceforge.net

It's a spam filter that works in the way you describe, is very good, is
free, has an excellent HTML-based user interface, and works with as many
email accounts as you like.

 

[william]

Looks like a nice freeware product, but it also needs to be "trained" like
SpamBayes.

This app does not need to be "trained" because it simply allows people in
your contact list to email you and adds people to your allowed list as you
send emails. Very simple concept and no "training" needed.

At this point, the project will take some time for me to figure out just how
they are placing themselves in between my Outlook and my email server. I
know that they change the POP and SMTP to point to the local IP 127.0.0.1
and change the outgoing SMTP port to 30, but I don't know all of the
specifics about whether they are simply relaying the requests from Outlook
or if they are doing more.

I loaded an app that filters out spam (as it puts it) "before it hits
your inbox". [...]
I figure it will be a good project to learn .Net on, and it would be
nice to offer as freeware.

Not wanting to stop you working on your project, but you do know about
POPFile?

http://popfile.sourceforge.net

It's a spam filter that works in the way you describe, is very good, is
free, has an excellent HTML-based user interface, and works with as many
email accounts as you like.

 

[william]

In addition to learnign how they do thier thing......I am considering an
addin for Outlook. Unfortunately, this seems to be another area that .Net
has complicated with no apparent reason.

The VSTO only works for Office 2003 (as far as I have read) and the new
security neasures incorporated in .Net are a pain in the ass that are not
only unneccessary but are also a stumbling block for other developers of
Microsoft add-ins.

Makes me wonder if Microsoft isn't making programming the system more
difficult on purpose with .Net - to stifle competition. Sure, the easy
things are easier.....but the hard (or uncommon) things are harder.

I may write the addin with VB6.....more straightforward and easier to
implement than the whole PIA/security fiasco that I am finding with VB.Net
2005 and Outlook.