Topic: So far this forum has been of 0 help but here is a proposal/question

Is there or has anyone ever heard of a email address validation checker plug in for user registration?

I have gone to one on the web and deleted about 20 fake email users on my forum.

I'd like to ad this into my system.

Re: So far this forum has been of 0 help but here is a proposal/question

We tried to run an SMTP-connection check, but most servers responded incorrectly. Do you have any ideas how to do this checking?

Re: So far this forum has been of 0 help but here is a proposal/question

Slavok wrote:

We tried to run an SMTP-connection check, but most servers responded incorrectly. Do you have any ideas how to do this checking?

I have left my SMTP field blank. - but i am not sure what your on to here.

Re: So far this forum has been of 0 help but here is a proposal/question

We tried to implement the email existence check the next way:
0. E.g. we have the email user@example.com
1. Find the mail server by MX-record for the example.com. Let it be mx1.example.com.
2. Connect to the mx1.example.com:25 via the socket.
3. After all necessary greetings, send the VRFY request giving the username user. The server must confirm whether this email really exists.
4. In real life most servers just respond OK.

Other way is to try to get the error on the wrong RCPT value. But most servers, again, just accept any wrong username, returning the OK.

This was tested on gmail.com, mail.ru and other public mail hosts: thy just ignore the RFC.

Carpe diem

5

Re: So far this forum has been of 0 help but here is a proposal/question

Slavok wrote:

We tried to run an SMTP-connection check, but most servers responded incorrectly. Do you have any ideas how to do this checking?

You can't do it reliably.

Anatoly, what do you class as, quote: 'all necessary greetings'?

Re: So far this forum has been of 0 help but here is a proposal/question

MattF wrote:

You can't do it reliably.

That's it.

MattF wrote:

Anatoly, what do you class as, quote: 'all necessary greetings'?

I don't remember the details, but HELO at least :-)

Some kind of:

S: 220 smtp.example.com ESMTP Postfix
C: HELO relay.example.org
S: 250 Hello relay.example.org, I am glad to meet you

http://en.wikipedia.org/wiki/Smtp#Sample_communications

Carpe diem

7 (edited by 3nrag3 2008-11-14 03:17)

Re: So far this forum has been of 0 help but here is a proposal/question

depending on what smtp server you are running you can block relaying of mail.
if you telnet or netcat to smtp.google.com 25 (just an example)
issue the command
helo example.net ......you will be greeted
issue the command
mail from: santa@northpole.com ........server will accknowledge
issue command
rcpt to: umpitysquat@gmail.com .... server denies relay.


Try doing this with your sever and see if it will relay the message or deny it.
then read the docs or man pages of the smtp mail server you are using and learn to how to stop it. (by blocking relaying of mail to non registered users will help...you could even require authentication....upon connection to the server (depending on which one your using).

Re: So far this forum has been of 0 help but here is a proposal/question

My idea is that it doesn't work as general solution as SMTP servers answer in different ways. So that we cannot rely on their information.
Nevertheless, there may be an extension to check the emails at some limited list of servers. But I see a little of use for it then.

Carpe diem