Problem using mail() function

AndyB40

Hello

I am successfully using the mail() function within a PHP script running at our ISP (Linux).

However this morning my ISP's mail server crashed for a while. At this point if the PHP script was being used, there would be no way of knowing that the mail was never sent (I am assuming this is what would actually happen).

I believe error trapping the mail() function is basically true or false depending on whether the parameters were passed across correctly or not.

Is there a way of error trapping the mail() command in case the sendmail server is not running for some reason.

I was thinking along the lines of some sort of exec() function or popen() function to see if the server is responding, but this seems very inefficient.

Andy.

dalecosp

The "host machine" was the mail server and the web server, and the mail portion was down but the web wasn't?

Otherwise, if mail() is using localhost, the mail should have been queued up until its gateway was back online.

Is there any reason this wouldn't work like it does for many?

if (!($success=mail($to, $subj, $msg))) {
   echo "Please try again later.";
   }

I have a feeling I'm missing something here .... 😕

AndyB40

Thanks for replying.

The code you show does indeed check whether the mail function is returned true or false. But I think it only checks, for example, whether the $to field is correct in terms of content. I don't believe it checks whether the mail was delivered or not to the server.

The "host" machine at the ISP does run the web and mail server, and it was the mail server that was down at the time, the web server was working without a problem.

So you think in this case the mail would have got queued until sendmail was back online? Where would the mail get queued, PHP knows what to do with it?

I am running MacOS X here, and have sendmail installed as well as Apache/PHP etc, and test my PHP code here first before uploading it to the ISP. Yesterday evening I tried turning the sendmail server off, then sent mail via PHP, and as expected no mail arrived. However I then turned the sendmail server back on and the emails arrived! So maybe they do get queued somewhere?!

I just want to make sure the emails get sent and lost in times where the mail server is not functioning for some reason.

dalecosp

What I was attempting to suggest what that if the machine on which your script runs was up, (both http and smtp services) and that machine used an external 'next-hop' server as it SMTP MTA, then the local machine would queue the mail until the 'next-hop' server came online.

I'm thinking it's a rather small ISP operation if everything's on one box. But, today's boxen can handle it, I guess.

Things are further complicated by what MTA is being run. In recent Sendmail builds, for example, there's a seperate queue for outgoing mail, and a seperate process that runs on a different port for these submissions. So, then it depends on what, exactly, was borken on the mail server.

Anyway you've brought up an interesting point.

As for your MAC OSX, I would assume that mail gets stuck in some dir called 'clientmqueue' until it's sent, but I dunno for sure. On BSD this dir is under /var/spool .....

AndyB40

Sorry. I had not made myself very clear. The machine at the ISP the script was running on does host both HTTP and SMTP services, but at some point the SMTP service may fail. In this case what happens to the mail being sent via PHP to localhost?

I understand that if the problem was the "next hop" server then sendmail would simply queue the messages until it came back online.

The ISP I am sure does have a main seperate server for handling its mail, but as this is Linux they have also had to provide sendmail on the same machine as our Web sites are running, as there is no way of telling PHP to send mail directly to another machine. PHP has to send mail to a mail server running on the same machine.

Good idea, I'll do some more tests on my computer, turning the sendmail server off, then trying to send mail via PHP, and see whether the mail gets put ina queue somewhere.

dalecosp

Originally posted by AndyB40
PHP has to send mail to a mail server running on the same machine.

Good idea, I'll do some more tests on my computer, turning the sendmail server off, then trying to send mail via PHP, and see whether the mail gets put ina queue somewhere.

That will likely depend on the system; as I mentioned, newer Sendmail has a client-mqueue, but I imagine if the server's OFF it won't work, either....

As for the assertion at the top of the quote, it's true to a point...but consider this thread before you decide for sure.

If you really wanted to make sure no mail got lost, it might be possible to do something like this:

$success=mail($to, $subj, $message, $head);
if (!$success) {
   $sock=fsockopen("my.isp.othermail", 25);
   // do some *raw smtp* here....
   }
if (!$sock) {
   echo "I tried two different servers and they both crapped out...";
   }

Certainly not easy, but some folks are trying it. I expect that you might actually be able to open the socket and write to it as we're talking about machines that likely trust one another....

AndyB40

Thanks for all the info, I'll look into it.

After seeing some other posts on various forums it might be possible to use a command such as:
$fd=popen("/usr/sendmail -t","r");

This way I could see if the sendmail server is accepting the "open pipe" request.

This might be easier than sending mail using sockets. Mind you, this would be a very good way (and faster) of sending mail and checking for errors along the way.