PHP mail() and sendmail (Unknown User error) - php

I'm having an issue with PHP mail() and the standard sendmail MTA on debian. I want to be able to send mail through PHPs mail()-function from "users" not existing on the system. As it works now I can send mail just as long as the user (user#domain.tld) exists. I want to be able to send mail from any "user", e.g from random#domain.tld where random may be a non existent "user".
Now to the real question; Is there any setting in sendmail that will allow this?

No setting needed, typically. You can send e-mail from anyone in the world... it's just a header.
However, you should know that spam filters are smart to this! There are numerous methods for checking that an e-mail was legitimate, such as SPF records and what not. It is poor practice to send from non-existent accounts, and your chances of ending up in a spam filter are quite high.

Related

What are the differences between sending email in PHP with mail, sendmail, and smtp?

I have heard that all of these methods are valid ways to send email in PHP.
What are their advantages and disadvantages?
The three options aren't quite in the same league, presuming the first means the mail() function.
Using the mail() function usually calls the local mail injector, commonly a binary program supplied by the MTA actually called "sendmail". The problem with mail() is that it is a non-straightforward interface with a number of gotchas and traps which are not well documented. This is because it mimics (IMO badly) the call to the Unix CLI mail command.
It is possible to call the local injector yourself, but this documented even less well. You may as well call mail(), anyway, since this is what the latter does.
Using SMTP comes with its own set of problems, however. If there is a local MTA that accepts and forwards mail, then it is not a bad solution. If there isn't, you will have to figure out which host you should be sending to. This will either be figuring out which external host should be doing your forwarding, or doing the actual MX lookup yourself. You will also need to know the SMTP protocol and be able to handle refusals for any reason. And you have to decide how you handle the need to re-try the send.
Doing the SMTP yourself also has the problem of not de-coupling the email sending from the reason the email is being sent. If there is a delay, or a problem, you have a page that will appear to be stuck. Using the local injector hands the former problem to the MTA; all you've done is queue the email for delivery. But then you don't have to worry about things like re-sending.
These three solutions also do not help you assemble your message, such as rich content, alternate content and attachments. You have to do all that (and add the correct headers!) yourself.
The normal recommendation is to locate a library that does all that for you, is robust and has a decent API. The usual one is PHP Mailer. The advantages of this library is that it also does all the message assembly, as well as figuring out how to do the delivery. But it's main win is that it Just Send The Message, trying mail() and local SMTP and even remote SMTP if it must. All transparantly.

PHP mails going into spam from Amazon Ec2

I have an application hosted on amazon EC2. Now a user can send out invitations to join but on most email clients its showing up in the spam folder. Is there anyway to find out on what criteria it is actually being filtered.
First of all, please check to see if your domain/IP has landed on any blacklists:
https://www.mxtoolbox.com/blacklists.aspx
Second of all, have you set an SPF record? Explanation below:
http://www.openspf.org/Introduction
https://mxtoolbox.com/spf.aspx
This is a way to qualify a particular server/IP as being a valid for relaying/sending mail on behalf of a particular domain. Sendmail - or whatever PHP is configured to use to send mail - can actually send mail for any user on any domain (i.e. "spoofing"). However the server receiving the mail (e.g. a recipients POP3 server where received mail is stored and filtered) is probably going to check whether or not that server is supposed to be sending mail for that domain based on what's in the domain's DNS entries. In particular, it will probably check the SPF record, so you will need to set this. You should consult whichever service manages your DNS (i.e. your nameservers) for how to do this. You can look up where your nameservers are using the whois, dig or nslookup commands (or just use a web based whois service) - look for the "nameserver" entries, often denoted by "ns".
This is one of a number of factors that may be affecting whether or not your mail goes to spam. This subject is something of a "can of worms" and goes way beyond setting up your PHP mail function correctly. Rather than trying to reiterate all of these issues here, I'll direct you to this post on serverfault:
https://serverfault.com/questions/106598/all-my-emails-to-yahoo-hotmail-and-aol-are-going-to-spam-though-ive-implemen
Do you use 5th parameter in mail function?
mail('reciever#address.com', 'the subject', 'the message', null,
'-fyour#address.com');
It helps sometime.
Also maybe your IP was blocked before you start to use it.

Php mail(), how to get undelivered address list?

I'm getting single emails, for each undelivered address that mail() send couldn't reach.
Since this can be a painfull process, to keep copy pasting every single address, I'm wondering if it's possible to access a LOG or something ?
Some notes:
- I've got this app running on a GoDaddy server (I know it sucks);
Thanks for your atention ;D
There is no log as such, because feedback from the receiving mail server is not immediate. There's only the "undeliverable" messages that get returned to you.
However, it should be possible to specify a reply-to or errors-to address pointing to a separate mailbox. That would make it easier to find out which recipient addresses failed.
That is the best way I can think of to group failed messages.
I'm wondering if it's possible to access a LOG or something ?
Maybe - it depends on what the MTA (mail transport agent) is, how it's configured and whether you have the permissions to access the file.
I've got this app running on a GoDaddy server
Then the above are all questions for your GoDaddy provider.
The MTA log should record details of messages which the MTA failed to offload elsewhere but the elsewhere may be a smart relay (i.e. still on the sending side) - in which case you'd need to look at the relay MTA's logs to see if it managed to pass the message on to one of the recipient MXs. Even if the message got as far as a recipient MX, you don't know that it was successfully delivered. By convention, the receiving system should send back a DSN if it fails (and you can specifically ask for a DSN regardless of outcome) but a lot of systems don't implement this properly.
Regardless it may provide information about some messages which fail - you'd need to poll the return mailbox to identify failures.
C.
If mail() fails immediately, it returns false and you went get any e-mail. However, if a problem arises after the mail has been sent but before it has been received, you get an e-mail.
The mail() function will send the e-mail to some mailserver, which will send it to another, until it reaches its destination. When the user does not exist, this is only discovered at the destination mail server and it responds with an e-mail, called a bounce.
There is no way to group these bounce e-mails, as the destination mail servers do not know that they came from the same script.
Another option you have is to pipe the incoming emails to a PHP script and process it that way. How this is accomplished depends on the server setup you have and whether your server is set up to use sendmail or exim.
A good tutorial on this is located here.

A couple problems re: CodeIgniter emailer

I have some problems with the email system for CodeIgniter:
First, the emails I send out (registration, confirmations) are getting caught in standard spam filters in gmail and other mail clients. How do I get around this? How do companies like Facebook get their emails through consistently?
Second, the mailer is working locally but once we deploy it it no longer runs (doesn't send emails) but all the other forms run just fine. Anyone ever run into a problem like this?
Thanks for all the help!
I can't really answer your first question - it's not specific to CodeIgniter. You just need to make sure your email doesn't look like spam. In short - there's no way of guaranteeing your e-mail will not end up in a spam filter.
As for the second question, I expect your production server needs to be configured properly for email. You probably need to configure CodeIgniter to send email properly. I would suggest setting up an SMTP server (or using an existing one) rather than using the standard PHP mail which I think CodeIgniter uses by default.
Regarding spam, most organisations are very secretive about how they prevent spam (not wanting to publish information which helps the spammers) and in some cases they don't actually know - an obvious examlpe of this is bayesian filtering - but, for example, hotmail use a completely unaccountable army of volunteers to manually classify emails.
Do and get a copy of spamassassin and try to reverse engineer how the standard rules work. Obvious things to check are:
1) AVOIDING LOTS OF CAPITALS
2) don't mention the 'V' word
3) make sure you've got a current and restrictive SPF 1.0 policy published
4) make sure your sending from an address which has A and PTR DNS records
5) Do provide a reply-to and from email address which use your domain in the address
the mailer is working locally but once we deploy it it no longer runs
doesn't send emails
Which? These are 2 totally seperate things. If the code is falling over (if so why have you not provided the error details) then its likely a PHP version issue or a problem with the connection to the MTA (or the PHP mail config).
The latter is a problem with the MTA itself.
99.9% of problems reported as PHP mail failures have nothing to do with PHP and are problems with the MTA.
Enabled detailled error reporting for your MTA and see where it is failing.
C.
You may have to configure the email on your server differently than your local development environment. I've had to in the past.
There are two basic ways that PHP can send mail:
Via a UNIX program called "sendmail" (only on non-Windows servers and only if it is installed - check with your hosting provider)
Via a SMTP server.
If you've configured CodeIgniter to use SENDMAIL, check to ensure that the Sendmail path is correct. Your hosting provider usually provides this somewhere in their online documentation.
If you're using SMTP, you need to make sure that your server can contact the SMTP server. You can do this by logging into the server via SSH and typing "telnet your.smtpserver.com 25". If you get an error message about not being able to connect, you know you have a problem with your hosting provider connecting to your mail server.
I've been able to diagnose this problem by enabling logging on my production server (http://bit.ly/4pprd6) and adding log_message('error', $this->email->print_debugger()) right after I attempt to send a message.

PHP mail() - Email not received

I have set up an AJAX contact form on a client's website.
The problem is that the email is not getting through to the client's inbox.
I set up the client with Google Apps (in the same way I did for myself).
I used the same contact form with my email address and it works. But with any email addresses on their domain it doesn't!
All members of the domain are receiving 'ordinary' emails.
What could be the difference that's stopping mail() emails getting through?
UPDATE
Ok so I managed to solve it. Turns out that using a CNAME to point the domain to the correct server wasn't enough for sendmail so I had to change it to an A record pointing directly to the server. Strange but true. Thanks for the help folks, you pointed me in the right direction :)
It depends on the both settings on your server and the server on the receiving end.
hotmail for example requires the use of correctly configured SPF records.
many mail-receiving servers (including hotmail) require the email to originate from a Fully Qualified Domain Name. It is very possible that your e-mails send from PHP do not comply with this rule. (there is a good chance they originate from 'apache')
see hotmail self help and hotmail postmaster info
PHP's mail() function does not include a lot of headers with your mail, so you will need to supply them yourself.
The more hops your mail makes on it's way to it destination, the more likely it is to be tagged as spam.
So it might be a better option not to use PHP's mail function and instead use a mail library that connects to an SMTP server just like your desktop mail application does.
All in all, I would place my bets on an external library: Pear::Mail (documentation)
You could also read: how do you make sure email you send programmatically is not automatically marked as spam
UPDATE
Failing the SenderId or SPF check can get your message dropped before it even hits the users inbox. The message will not end up in the users junk folder, it will go directly to /dev/null.
I know this is at least true for hotmail and live mail. I see no reason for other hosts not to have implemented the same policy.
I recommend using PHPMailer (including their SMTP) library instead. It is reliable compared to mail and allows you to create fully customized emails.
http://phpmailer.worxware.com/

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