smtp

[Crossett]

Why will the mailer object only send e-mail notifications to local servers.

I'm trying to send an e-mail to an address outside our network but get errors in the log file and the e-mail is not sent.

Here's the log file

[[NEW SEND]]
SMTP>220 adsl-69-109-6-66.dsl.renocs.pacbell.net Microsoft ESMTP MAIL Service, Version: 6.0.3790.1830 ready at  Thu, 1 Dec 2005 09:35:45 -0800
LK>HELO MARKC
SMTP>250 adsl-69-109-6-66.dsl.renocs.pacbell.net Hello [192.168.15.75]
LK>MAIL FROM:<markc@sierracontrols.com>
SMTP>250 2.1.0 markc@sierracontrols.com....Sender OK
LK>RCPT TO:<mcdrak@cablespeed.com>
SMTP>550 5.7.1 Unable to relay for mcdrak@cablespeed.com

I've tried different SMTP servers and as long as i use the same SMTP server that the recipient is using, the e-mail will go through. This is not good when I'm trying to send the e-mail to several recipients with different domains.

Using Lookout 5.1 build 7

I've tried this on 3 different computers, all with the same result

[Khalid]

Hi Mark,

Have you tried the following test:  while Lookout being on domain1, you use domain1's mail server to email a domain2 user?  I am pretty sure that would work.  This is because SMTP assumes the mail is being sent from within the domain (in our test, Lookout was on domain1 and you used domain1's mail server). 

I am guessing you tried using "external" SMTP servers (i.e., those different from what Lookout is on).  To send mail using an "external" mail server (for instance that of an ISP) is tricky.  I know of two options; there are more:

(1) ESMTP, and
(2) POP-before-SMTP.

ESMTP:  'Enhanced (extended?) SMTP' has authentication and accepts username and password.  Not all mail servers suport ESMTP, however. In any case there's no option in Lookout's Mailer object to send username and password, so that's ruled out.

POP-before-SMTP:  Looks like most ISPs use this mechanism. The idea is that the user first "POPs" the mail server, i.e., connects via POP (and retrieves?) the mail.  When this happens the IP address of the user is logged (this mechanism is called POPAUTH).  From then on and for the next 15 minutes (default), the user from that IP address can send mail using the SMTP.  This is mainly to prevent unauthorized "relaying" of mail by spammers and others.  And that's the "Unable to relay" error you're getting.

By the way, emailing users local to the SMTP server is not considered "relaying," which is why you observed  "...as long as i use the same SMTP server that the recipient is using, the e-mail will go through..."

So, what is the solution?  I guess the easiest would be to use the mail server from the domain on which Lookout resides.  If you have to use another SMTP server, you may want to "POP" the server first by reading email off of it somehow -- this doesn't seem very practical.  Maybe you could talk to the ISP / Mail server administrator to make an exception for mail coming from the Lookout machine (IP address); again not sure if this is doable. 

Well, I hope this helps in at least understanding the problem... if not in solving it  

Regards,

-Khalid

Message Edited by Khalid on 12-03-2005 12:20 AM