Thanks, that was very clear :) -----Original Message----- From: Roman Neuhauser [mailto:neuhauser@xxxxxxxxxx] Sent: Friday, October 13, 2006 6:32 AM To: Richard Lynch Cc: Peter Lauri; php-general@xxxxxxxxxxxxx Subject: Re: PHP Mailer and SMTP = SPAM? # ceo@xxxxxxxxx / 2006-10-12 11:23:52 -0500: > On Wed, October 11, 2006 11:28 pm, Peter Lauri wrote: > > [snip] > > Unless the email is coming "from" somebody the recipient knows/trusts, > > then you're going to get marked by them as a spammer -- which will > > report back to some of the lists marking you as a spammer. > > [/snip] > > > > But is it not a problem sending from the SMTP server thedomain.com > > using something else then the email thename@xxxxxxxxxxxxx? I am > > planning to send from an existing email from the domain. > > Not really -- at least not in my limited experience. > > There are so many OTHER factors that the DNS resolution of the return > address and the actual SMTP machine not matching up are probably not a > deciding factor... Sender, client.example.org, IP 1.2.3.4 connects to the receiver (server.example.org). 1. DNS - PTR RR. If 4.3.2.1.in-addr.arpa doesn't exist (the value would be client.example.org), server refuses the connection 2. DNS - A RR. If client.example.org doesn't exist or doesn't resolve to 1.2.3.4, server refuses the connection 3. DNS - RBL. If 1.2.3.4 is in any of a number of possible RBLs, server refuses the connection 4. DNS - RHSBL. If example.org is in any of a number of possible RHSBLs, server refuses the connection If the client passed all checks, the server accepts the connection: S: 220 server.example.org ESMTP C: HELO client.example.org S: 250 Ok 5. SMTP - If client doesn't say HELO with a FQDN argument, or 6. SMTP - If the HELO command argument doesn't resolve to the client IP address, the server responds with a 4xx or 5xx. C: MAIL FROM: joe@xxxxxxxxxxxxx 7. DNS - MX or A RR. If neither of these records exists for elsewhere.org, server replies with 5xx, permanent error. S: 450 Greylisted C: QUIT server replied with a 4xx temporary error code, the client (rightly) disconnected. server in turn tries to send a message back to joe@xxxxxxxxxxxxx to see if it accepts email: E: 220 erwin.elsewhere.org ESMTP S: HELO server.example.org E: 250 Ok S: MAIL FROM: <> E: 250 Ok S: RCPT TO: <joe@xxxxxxxxxxxxx> E: 250 Ok S: QUIT The empty FROM address is the special null address used to send bounce messages. Should erwin reply with 5xx to any of the commands from server, joe@xxxxxxxxxxxxx will be stored in a nondeliverables database, and when client returns it'll be rejected: C: MAIL FROM: <joe@xxxxxxxxxxxxx> S: 550 Sender rejected I'm sure I forgot something or screwed the description here and there, but you get the idea. -- How many Vietnam vets does it take to screw in a light bulb? You don't know, man. You don't KNOW. Cause you weren't THERE. http://bash.org/?255991 -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
