Best options for sending confirmation email

To not be filtered

[Sierra_Dad]

My content management has three choices for sending the automated confirmation email:

Sendmail
PHP mail
SMTP

Which is the best option?

I thought maybe SMTP might be better than the others, since the sendmail will be on the server with shared hosting, and the IP Address may not mathcmy domain.

I don't want to look like spam so that my messages get dropped. It is apparent that at least some are being filtered into bulk folders in yahoo.com and gmail.com using PHP mail.

I was hoping for better results using smtp. But there may be little I can do about it except educate the customers.

[coopster]

Sounds to me like your CMS is using the PEAR mail package [pear.php.net]. I don't think you need to be concerned as much with which method to use, rather make sure your mail headers are well-formed.

[jatar_k]

and make sure your content doesn't trip any spam flags

take a look at this list for tests on what trips spam flags
[spamassassin.apache.org...]

[coopster]

Hey, great resource. Man, I've been on the apache site a million times and never knew that was there. Thanks pal ;-)

[Sierra_Dad]

The content itself seems to score extremely low on spam tests.

The headers are formed by the CMS (Mambo) but I believe I can find the code. What do I look for in the headers?

I see one thing that may be worrisome.

Return-path: <[e-mail]>

Where I would expect to see
Return-path: <[e-mail]>

But I can't actually see in the code it is adding this header, or maybe it is added automatically by sendmail or something.

And it does seem that the users that never confirm their registration are predominately from gmail.com or yahoo.com. They might just have some aggressive spam filters that just put everything new in the suspect file. A gmail user just complained about not getting the confirmation email. Unfortunately, he will probably never get my reply.

[directrix]

take a look at this list for tests on what trips spam flags
[spamassassin.apache.org...]
I like the RESISTANCE_IS_FUTILE test -- got to be careful about unassimilated email.

[coopster]

Return-path:

can be a bear, but that is why PHP offers us the additional parameters in the mail() function. It all comes down to how the sendmail utility is setup on your server and whether or not you are sending off a

Return-path:

header. If you include a

Return-path:

in your mail headers and it still isn't working correctly, then the sendmail utility might be overriding your header. A "for certain" solution is to add the additional headers to your mail() function, something like

'[e-mail]'

[Sierra_Dad]

I've hacked some the mailing code to explicitly set the Return-path to another address at the same domain.

I don't know whether this will make a huge difference, as I didn't see this mentioned as a factor in the spam tests.

I'll be putting up notices on my web site in hopes that people can check their ISP for filtering if it occurs.