I'm sending newsletter using Zend Mail. I have used setReturnPath() to put all undelivered mail notifications in one place.
And what now?
How to get the list of addresses which were unreachable?
How do I read and parse the returned notifications?
How to know whether the mail returned because of non existing email or just quota exceeded?
Which headers do I need to send and check?
Related:
Variable Envelope Return Pathwiki
Handling undelivered emails in web appso
This class may be helpful. Can determine whether the mail is a bounce and return a response code with description:
http://www.phpclasses.org/package/2691-PHP-Parse-bounced-e-mail-message-reports.html
Short Answer:
you can't do that in a simple way and not in your app.
Long Answer:
You should handle that in asynchronous way and outside your php app (at least in part). First of all you must setup the return address to something like sender+recipient=recipientdomain.com#senderdomain.com as in the TimB answer. At this point all the notification sent by receiving smtp server will go to that address.
Then you need to setup the smtp daemon at senderdomain.com mail exchanger to handle that kind of bounce messages and process them in some sort of pipe.
With a pipe you can forward the returned message to an external program which parse the message and extract the needed informations (i.e. the reason why the delivery is failed)
At that point in your program (which can be a cli script in your application) you can mark the address as failing and optionally can record why.
This is a pretty difficult task, which can't be handled in a simple application. Usually I use a dedicated software for large mailing list handling such as sympa which takes care of this task for you.
Otherwise you can use an external delivery service such as Sendgrid which will do the dirty job for you and report the failing addresses with a simple API. As a bonus with this solution, they are in the whitelists for all the major providers, so your email won't be marked as spam as far as you respect some simple rules (i.e. removing bouncing addresses and use an opt-in policy for your newsletter)
Well, the second link and especially the answer by TimB explains very well the procedure.
What may not be clear is that the return path is nothing other than a regular email account, i.e. you will get the email to that address. Zend_Mail is not waiting for a response and hence there is no list of addresses.
Related
Given there is a "FAILTO=''" option for cfmail, triggering an email to be sent to that email if the email didn't get delivered...
Is there a way to somehow assign an ID or tracking # to an email, store it in a database with that ID... then update the status of that email if it fails?
I'd like to track bouncebacks... preferably WITHOUT sending the FAILTO to a POP3 or IMAP and then checking it with cfimap...
Is there any alternate way of handling this?
Maybe an event gateway that is triggered upon email failure?
UPDATE: I've decided to take a different approach, utilizing the sendgrid API.
I'm hoping that lends me with a few more tools than CF offers.
The short answer to your question is unfortunately no.
A longer version with a possible solution:
The failTo email address populates the return-path in the email header, this then 'should' be used by mail servers for bounce backs (however see - http://www.bennadel.com/blog/1899-GMail-Seems-To-Ignore-The-Return-Path-Header-Defined-By-The-CFMail-FailTo-Attribute.htm for an example where it doesn't)
So you are going to need to monitor an Imap or pop account to see your mails, however you can set up an event gateway to monitor this, with detailed instructions here - http://www.alagad.com/documentation/imapGateway/ImapWatcher%20Gateway%20Documentation.pdf
What you're left with is needing to identify which mail matches which bounceback, when I've done something similar in the past I used unique id's for the failTo email addresses at a domain I owned. If you set that up and then use your listener cfc to look for the id in the return-path.
So your sending code would work along the lines of:
Generate unique id
Send mail
Add row to database with unique id
Your listener.cfc would then need to inspect the email returned and if it finds the unique id update the row with whatever information that you're after.
Hope that that at least helps even if you'll need to set up some other bits.
You could use a directly watcher on the undelivr folder to log the failed emails, only really a solution if its own server and not a shared server though.
As far as I know once it leave the spool and is off to your SMTP server CF assume it's been sent correctly.
The email will trickle down the chain of SMTP servers/relays and if anything happen the only instruction they have is to bounce it back to the from address or failto address if present. CF isn't listening at this point so it can't respond.
We use an external tool called Glock email processor to handle exceptions. It's not free, but works pretty well. You can find it here: http://www.glocksoft.com/email-processor/
You need to configure it to check the failto address and from there you can take many actions. I got it setup as a three strikes system.
Email address bounce, I increment a counter in my email table, at 3 I deactivate that email from the system.
Nothing you can't do yourself with cfpop though.
I have a need to "bounce" email from a specific email address. Meaning, when this person emails me I would like them to receive the MAILER_DAEMON message saying that the email address is no longer valid or some other "official looking" message that would make them believe that the email address (mine) is no longer valid.
Is it possible? I have Gmail but I am also a programmer so I would not be afraid to get my hands dirty with some kind of "server" that takes forwarded emails and then re-routes them or anything creative like that.
Any suggestions?
Apple used to include this feature in their mail app. There was a menu item
labeled "bounce" If you integrated into say, Thunderbird, you should be able to send the bounce. Alternatively, google has gmail API's that can read and send from your gmail account.
A Delivery Status Notification message is not hard to create on your own. You might have to tweak something to properly set an empty envelope sender (so as to produce an empty Return-Path:), but other than that, just write a reply with the desired text, and invoke it from your .procmailrc or whatever.
If you have direct access to the delivery machine, you might get away with just returning a particular error code, and the MTA will bounce the message for you, but the exit code depends on the MTA. Many implementations use Sendmail's conventions, but e.g. qmail has its own. http://www.eden.net.nz/7/20011101pairprocmail.html explains this from a Procmail perspective in some detail, and has the pertinent exit codes for both Sendmail-compatibles (which includes Postfix) and Qmail.
:0
* ^From: Annoying Perp <troll#example\.com>
{ EXITCODE=67 HOST= } # Exit with Sendmail code for "no such user"
The Postfix document http://www.postfix.org/FILTER_README.html explains the processing model in much more detail -- some of it is specific to Postfix, but as with all the Postfix documentation, it is understandable and helpful to the technically adept reader.
If you want to roll your own, your first stop would be RFC 3464; it's not a very tough read.
The Postfix bounce(5) manual page is very hands-on.
I work at a university, on a project for a web driven academic management system and I'm currently facing the following problem:
Sometimes the application needs to send e-mails, most of then are sent on demand (users ask for a password recovery link, for example). Many emails for this kind of service are sent daily, and if on a peak of access they are sent massively. This has caused our email server to be included in blacklists of common email providers (like yahoo and hotmail), resulting in failures on email delivery.
What are the common causes for this kind of problem? Is it possible to avoid these blacklists? Or at least is there any good practices to follow so I can "flag" these useful emails as non-spam or safe email?
thanks for reading.
first of all, check if those messages are really sent to email addresses in your account database. maybe there is a security hole in your application that allows sending messages to arbitrary recipients. an indicator of that would be if your domain or ip is blacklisted not only at specific providers like yahoo or hotmail, but also on public blacklists like spamhaus.
("most of then are sent on demand".. makes me think.. what about the others? could they be interpreted as spam by many recipients?)
then you need to find out if your server is blocked due to
the amount of messages sent or due to the content looking "spammy".
Check your logs from the time before the blacklisting happens. Do you see many deferred messages (4xx error code), do they contain error messages that indicate too many messages from your IP?
if so, configure your MTA to throttle message delivery to those providers.
also check your mailserver setup:
correct fully qualified HELO?
matching reverse dns?
If you have DKIM , SPF and the like... are the settings correct?
finally, examine the generated messages. Do they have all required headers? Run them through spamassassin and check the result. adapt the formatting of your messages accordingly.
A number of applications have the handy feature of allowing users to respond to notification emails from the application. The responses are slurped back into the application.
For example, if you were building a customer support system the email would likely contain some token to link the response back to the correct service ticket.
What are some guidelines, hints and tips for implementing this type of system? What are some potential pitfalls to be aware of? Hopefully those who have implemented systems like this can share their wisdom.
Some guidelines and considerations:
The address question: The best thing to do is to use the "+" extension part of an email (myaddr**+custom**#gmail.com) address. This makes it easier to route, but most of all, easier to keep track of the address routing to your system. Other techniques might use a token in the subject
Spam: Do spam processing outside the app, and have the app filter based on a header.
Queuing failed messages: Don't, for the most part. The standard email behavior is to try for up to 3 days to deliver a message. For an application email server, all this does is create giant spool files of mail you'll most likely never process. Only queue messages if the failure reasons are out of your control (e.g., server is down).
Invalid message handling: There are a multiple of ways a message can be invalid. Some are limitations of the library (it can't parse the address, even though its an RFC valid one). Others are because of broken clients (e.g., omitting quotes around certain headers). Other's might be too large, or use an unknown encoding, be missing critical headers, have multiple values where there should only be one, violate some semantic specific to your application, etc, etc, etc. Basically, where ever the Java mail API could throw an exception is an error handling case you must determine how to appropriately handle.
Error responses: Not every error deserves a response. Some are generated because of spam, and you should avoid sending messages back to those addresses. Others are from automated systems (yourself, a vacation responder, another application mail system, etc), and if you reply, it'll send you another message, repeating the cycle.
Client-specific hacks: like above, each client has little differences that'll complicate your code. Keep this in mind anytime you traverse the structure of a message.
Senders, replies, and loops: Depending on your situation, you might receive mail from some of the following sources:
Real people, maybe from external sources
Mailing lists
Yourself, or one of your own recipient addresses
Other mail servers (bounces, failures, etc)
Entity in another system (my-ldap-group#company.com, system-monitor#localhost)
An automated system
An alias to one of the above
An alias to an alias
Now, your first instinct is probably "Only accept mail from correct sources!", but that'll cause you lots of headaches down the line because people will send the damnedest things to an application mail server. I find its better to accept everything and explicitly deny the exceptions.
Debugging: Save a copy of the headers of any message you receive. This will help out tremendously anytime you have a problem.
--Edit--
I bought the book, Building Scalable Web Sites, mentioned by rossfabricant. It -does- have a good email section. A couple of important points it has are about handling email from wireless carriers and authentication of emails.
You can set the address that the email is sent from, what will be put into the To: address if someone just presses 'Reply-to'. Make that unique, and you'll be able to tell where it came from, and to where it must be directed back to.
When it comes to putting a name beside it though '"something here" ' - put something inviting to have them just reply to the mail. I've seen one major web-app, with Email capturing that has 'do not reply', which turns people off from actually sending anything to it though.
Building Scalable Web sites has a nice section on handling email. It's written by a Flickr developer.
(source: lsl.com.au)
EDIT: I misunderstood your question.
You could configure your email server to catch-all, and generate a unique reply-to address. E.g. CST-2343434#example.com.
A polling process on the server could read the inbox and parse out the relevant part from the received email, CS-2343434 could mean Customer Support ticket ID no. 2343434.
I implemented something like this using JavaMail API.
Just a thought.
The best way to achieve this will be to write a window service that acts like a mail client [pop3 or imap]. This windows service should execute a timed action triggered by a timer, which connects to the mail server and polls the server for any unread message(s) available in the email inbox. The email ID to check for is the email ID on which the users will give their input on/to. If the windows service client finds that there exists any new mail(s) then it should download and filter the email body and push further for processing based on the user input in the email. You can host the input processing in the same windows service but it is not advisable to do so. The windows service can put the inputs in a special application directory or database from where your main appication can read the user inputs received in email and process them as needed.
You will be required to develop a high performance TCP/IP client for doing so. I advise you not to use the default .Net library due to performance issues, instead use one of the best availabel open source TCP/IP implementations for .Net like XF.Server from kodart. we have used this in our applications and achieved remarkably grear results.
Hope this helps..
Bose has a pretty great system where they embed a Queue and Ticket ID into the email itself.
My company has the traditional Case # on the subject line, but when CREATING a case, require a specific character string "New Case" "Tech Support Issue" on the subject line to get through the spam filters.
If the email doesn't match the create or update semantics, the autoresponder sends an email back to the recipient demonstrating how to properly send an email, or directs them to our forums or web support site.
It helps eliminate the spam issue, and yet is still accessible to a wide technical audience that is still heavily email dependent.
Spam is going to be a bit of a concern. However since you are initiating the conversation you can use the presence of your unique identifier (I prefer to use the subject line - "Trouble ticket: Unable to log into web...[artf123456]") to filter out spam. Be sure to check the filter on occasion since some folks mangle the subject when replying.
Email is a cesspool of bad standards and broken clients. You need to be prepared to accept almost anything as input. You will need to be very forgiving about what kinds of input are tolerated. Anything easy for you to program will likely be difficult for your users to use correctly. Consider the old mailing list programs that require you to issue commands in the subject line. Only hardcore nerds can use those effectively. And some of those trouble-ticket CRM things you mentioned have bizarre requirements, such as forcing the user to reply between two specific text markers in the text. That sort of thing is confusing to people.
You'll need to deal with email clients that send you formatted text instead of plain text. Some email clients still don't handle HTML properly (cough GMail) so your replies will also need to be designed appropriately. There are various ways in which photos might be "uploaded" via email as well, especially when mobile phones are involved. You will need to implement various hacks and heuristics to deal with these situations.
It's also entirely possible that you will get email that is valid but unusable by the email parsing library you are using. Whether or not this is important enough to roll your own will be a judgement call.
Finally, others have mentioned using specific email addresses to uniquely identify a "conversation". This is probably the easiest way to do this, as the content of the mail will often not survive a round trip to a client. Be prepared, however, to get mail to old IDs from old customers who, instead of opening a new ticket somehow, reply to an old ticket. Your application will probably need some way to push emails with an old ID into a new case, either manually or automatically. For a CRM system it's very likely that a user would reply to an old email even if you already sent him a new email with a new ID in it. As for whether you should use some.email.address+some.id#yourdomain.com or just some.id#yourdomain.com, I'd go with the latter because the plus-sign confuses some email clients. Make your IDs guids or something and have some way to validate them (such as a CRC or something) and you'll get less junk. Humans should never have to type in the GUIDs, just reply to them. The downside is spam filtering: a user's computer might view such email addresses as spam, and there wouldn't be an easy way to whitelist the addresses.
Which reminds me: sending email these days is full of pitfalls. There are many anti-spam technologies which make it extremely hard for you to send email to your customers. You will need to research all of these and you need to be careful, and do some testing, to ensure that you can reach the major email providers. A website like Campaign Monitor
can help you if you are sending email.
Our clients sometimes don't get the emails that we send out. It's a BIG loss. How do I assure that they receive the emails so that if it's not received in the other end, the program can resend it or do something about it.
None of the suggestions above will work 100% of the time. Many email clients will (rightly so) refuse to load foreign images, negating the usefulness of "web bugs". They will also refuse (or be unable to) return Outlook-style "receipts". And many mail servers either deliberately (to curb spam) or mistakenly (due to misconfiguration) won't return bounce messages. Or possibly an over-aggressive spam filter ate your message, so it arrived but was never seen by the end user. Plus there is the little matter of mail taking hours or days to reach the end user or bounce, and how do you correlate these late notifications or bounces with the mail you sent 4 days ago?
So basically, you can catch some but not all, no matter what you do. I'd say that any design that relies on being able to know with certainty whether the end user got your mail is fatally flawed.
One thing that you can do is set up a bounceback address that receives any mail that is undeliverable. Use the bounceback address as the From address -- you may want a different one for Reply-To so that replies get directed properly.
Check the bounceback mailbox daily and contact customers to get updated email addresses for the ones that fail. You may be able to automate a couple of retries to failed addresses before resorting to the manual contact in case the failure is only intermittent.
This would take some code outside your application that scans the mailbox and keeps some state information about the number of contacts, etc. and attempts the resend.
Depending on how you generate the mails, you might be able to make this process easier: generate a unique bounce address for every single email you send out. You could use bounces+1234#example.com, for example.
Many SMTP servers will allow you to use the part after the + as a parameter to an external script, etc.
The problem is that many (broken) SMTP servers don't return enough info with a bounce to identify the original message -- sometimes, when there are forwardings involved, you don't even get back the original addressee...
With the above trick you can reliably correlate outgoing messages with incoming bounces.
There is no standard way to know whether the email reached the destination. Many email clients support different types of receipts though. You can use any of those if you want.
There are some ways to know when the user actually read the email.
There are many techniques like adding an image to your email that is to be fetched from your web server. When the user reads the email, the request for the image comes to your server and you can capture the event.
The problem is that there is no way to know that the mail did not reach the destination.
I worked on a bulk email system in a previous life. Deliverability was one of our major issues. The most common cause of undelivered emails is a spam filter.
Here are the steps we took to ensure the highest delivery rates:
We used Return Path to test emails for that spam-like smell.
If you send a lot of emails, you need to make sure your SMTP server is not blacklisted.
Remind your users to add your FROM address to their "safe senders" list.
Use a system that collects bouncebacks and use them to scrub your mailing list. This will also help keep you off the blacklists.
If the emails are critical, consider sending them return-receipt-requested. This will not really guarantee anything, but it might give you some metrics on actual deliverability.
There's not really a good way to determine if the email actually arrives in their inbox, you can only confirm that you sent it. Attach a receipt that lets you know when they open it perhaps?
Microsoft Outlook provides similar functionality, however it is based on the email client. I'm not sure if other clients, like Thunderbird, support this.
However, there is nothing in the protocols that specify receipts.
One option that may work: send a link to a generate web page and monitor that page for hits. This provides its own issues however: confidentiality, etc.