Posted by Jerry Stuckle on 05/01/07 12:25

Jim Carlock wrote:
> Max wrote:
>> Our mail server accepts emails from the webserver. Our emails are
>> going through default MX records, which point to our ISP server, which
>> does relay emails to our mail server. Simply put, I want to bypass the
>> MX record (which points to the ISP server's SPAM filter, which works
>> for us for all other mail, we have no control over)
>
> "Jerry Stuckle" <jstucklex@attglobal.net> wrote:
> : In that case you'd have to look at your Unix/Linux configuration. PHP
> : knows nothing about MX records.
>
> MX is pure DNS. It points to a mail server which usually opens port
> 25 up for SMTP and port 110 for POP3. PHP tends to run under an
> Apache server which in turn opens port 80, unless one configures
> weird/different things with port numbers.
>
> Note, every IP address includes a port number, and a full connect
> cannot be established without supplying the 5th element of the IP
> address (the port number).
>
> 11.11.11.11:80 is a different IP address than 11.11.11.11:25.
>
> When an SMTP server wants to relay mail to your mail server, it
> issues an MX (DNS) query. PHP runs underneath Apache, but
> I thought I read something somewhere that PHP can make and
> accept connections on other ports. Perhaps, I'm getting it mixed
> up with some Perl things I've read?
>

Sure, PHP can make and accept connections on other ports. It has
nothing to do with running under Apache. But PHP knows nothing about MX
records.

In fact, it knows nothing about A records, either. All it knows it it
can connect to a server by name, TCP/IP performs the DNS lookup
transparently.

> Anyways, that tends to be the way I think of it all. Please correct
> me if anything I've stated is wrong.
>
> http://us2.php.net/manual/en/ref.sockets.php
> http://us2.php.net/manual/en/function.socket-bind.php
> http://us2.php.net/manual/en/function.fsockopen.php
>
> It almost appears that PHP can become a fully functional SMTP
> server and/or POP3/IMAP server.
>

It could be. But there's no implementation - and I suspect there never
will be. A SMTP server is quite complex. A POP3/IMAP server is less
so, but still complicated. Both would be quite slow in any interpreted
language.

--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attglobal.net
==================

[Back to original message]