Posted by Max on 04/30/07 16:19

I have read the php.net mail manual and am aware of the SMTP MTA
Windows redirect. The manual reads that php.ini SMTP string can be
configured for Windows servers only. I am aware of that. What I am
trying to accomplish is - to make it work in Linux setup.

Here is our scenario:

We have the following setup (I am rewriting the actual values for
security purposes):
The mail server's IP is 111.111.111.111 which resolves to
mail.mysite.com
The webserver's IP is 222.222.222.222 which is www.mysite.com or
mysite.com

To prevent increasing SPAM attacks we modified the Mail MX records to
point to our ISP, which has the SPAM filter installed on their server
(121.121.121.121). All the SPAM filter does is - it strips sender
email's domain part and verifying it with sender's IP. If it is a
match, then ISP's server relying it to our mail server
(222.222.222.222)

Webserver's sendmail is working properly, but what happens is:
111.111.111.111 -> 121.121.121.121 X 222.222.222.222

When the email is originated at 111.111.111.111 - mail.mysite.com
(using PHP mail() function), the ISP's filter reads the sender email
address, compares it with IP, arrests the email, replying "You are not
222.222.222.222" and tries to bounce it back to 111.111.111.111.

We need to bypass that route for mail originated on the webserver,
hopefully by rewriting php.ini.

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