automatic emails filtered by anti spam

[tomajacar]

hi there,

my website is fairly recent and is a typical classified ads site.
For each new ad on the site, we require an activation by email.
Then advertisers get contacted by email through the system.

I happen to think that the activation emails we trigger are blocked by many spam filtering systems and I can't understand why.

email contacts may also get blocked since they're triggered by the same server. There I may have an explanation as we spoof the sender email address so that it looks like it comes from him/her (not the brightest idea we ever had)

Could that also explain that the server is already classified as suspect by spam filters?
Could you advise on best practice in both cases, or direct me to some reading please on good and robust email practice?
Any little help really...
thanks in advance,

[jtara]

There I may have an explanation as we spoof the sender email address so that it looks like it comes from him/her (not the brightest idea we ever had)

If the sender's domain has an SPF record, and the SPF record restricts the servers from which mail can be sent, then this certainly is a problem. Servers that observe SPF are just going to drop it on the floor.

In this case, you could check the SPF record yourself, and give the user an error message, instead of letting them think that this is going to work.

Now, there is a nuance: just how are you spoofing the address?

SPF only checks the "envelope sender", not the "from" address. Are you spoofing only "From:", or the envelope sender as well?

[piatkow]

Address spoofing always causes problems even when legitimate. If you are spoofing a Hotmail address from outside Hotmail for example it will always be rejected.

Automated response systems always seem to create problems with spam filters. I have never had to set one up so I have have never needed to go into the mechanics but I know of two web hosting companies whose ticket system emails are never delivered by Hotmail and have similar problems with other major webmail providers.

[tomajacar]

sorry for the late reply. i had to do a bit of research to understand SPF, plus a few technical issues arose on the site (I am sure most of you know the feeling :))

Below is what a contact email looks like as far as "envelope" and "from" are concerned:

Received: from www-data by <server name> with local (Exim 4.63)
(envelope-from <[e-mail]>)
id 1IcnTz-0005J8-06
for <recipient email>; Tue, 02 Oct 2007 21:32:39 +0200
To: <recipient email>
Subject: <subject>
X-PHP-Script: domain/index.php for <IP address>
From: <sender name> <sender email>
Reply-To: <sender email>

hope that helps (to help),

Re spoofing, I guess an alternative is to just have the "reply-To" populated with the sender address, with a bit of text saying "you can reply to that email blabla"...

Finally, would that help to have messages in the body of the email such as "you receive that email because etc... Please click on authorize the recipient of that email" in order to get white listed?

Hope all these questions are not too confusing, but I am struggling to find a good and robust documentation on best practice for automated emails...