Detecting email client of the recipients - email

We are planing to develop an extension for a software which will detect the email client software or interface of the recipients and report it.
In many forums this subject is told that is not possible but in this site they claim that they provide a reporting in a large scale.
http://www.adestra.com/email-client-detection-with-messagefocus/
I would be glad if someone could tell or show me a way to do it in any platform.

There are 2 situations here:
- detect the client email agent of the sender
- detect the client email agent of the receiver
The SMTP protocol does not define anything that would allow you to identify the client agent. So in theory you cannot guess it. Some clients will send some sort of identification in the header, though also this is not standard, and it can be fake. You can guess the client agent base on these identifiers though.
To find out the client agent of the receiver, you need to include content that will eventually connect to an http server. From there you can get the client agent (of the browser that opens it). So again, you have to do some guessing work. (ex. if it's yahoo.com and it is chrome .. then .. if it's ie then .. and so on.)
So to cut it short, there is not reliable way of finding out the client mail agents, it's more guessing and statistics.

The only way to do this is via the user-agent from a tracking image, you need the interaction via http. From there, you could determine, although not reliably, the email client in use.

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I am creating an email spammer, for an outstanding cause [closed]

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In Cuba, web access is extremely censored, so I created a tool that allows more than 50,000 people to browse the Internet through email. Cubans send me an email with an URL in the subject line, and I email them back with the response. Read more at https://apretaste.com.
It was working like a charm, till the communist government of Cuba started blocking my emails. My solution was rotation.
I started with Amazon SES, and I was changing the domain each time it was blocked, but Amazon adds a header to all emails, and once they blocked the header no email from SES was able to reach Cuba any more. The same happened with Mailgun and others, they all add headers.
Currently I am creating Gmail accounts and sending via SMTP, but Google blocks me for no reason and only allows to send 100 emails a day per account. Also I can only create few emails using the same IP address/phone, so I was forced to use anonymous proxies and fake Chinese phones. Now I am fighting a war on two fronts.
An email can be blocked by three parameters: IP address, domain, and email address.
It will be terrific if I can set up my own Postfix server at a VPS that auto-rotates the IP address. Even better if I can simulate "gmail.com", to avoid purchasing a new domain every day.
All the intents to create what I call "the ultimate sender" just either reach the spam folder or add unwanted headers making it too easy to block. I feel exhausted. I hit a knowledge barrier here.
I know I am crossing to the dark side, but this is for a very good cause. Thousands count on this service as their only source of unbiased news, social network and to feel part of the 21st century.
Can you please help me implementing "the ultimate sender", or pointing to another solution that I may be missing?
I have a few suggestions for you.
The first one relies on The Onion Router also known as Tor.
Since you are crossing to the dark side, why not also take a look into the darknet?
Take a look at this list of Tor email providers. If you have your own email server that can be accessed through Tor, it becomes much harder for anybody to stop people from using this service. After all, Tor was developed to offer people uncensored access to the web.
You can read about Tor in detail here, it uses Onion Routing and this is how you would set up your server to use Tor.
Here is an example how you could use it:
The steps that involve the setup, receiving an URL request and sending back the reply are as follows:
Set up an email server.
Configure your email server to use Tor.
Publish the public service name. (e.g. "duskgytldkxiuqc6.onion")
Deploy a client that takes the service name and a URL, and let it send an email with a request to your server.
The client now waits for a reply.
You send a reply and the client receives it.
You can change your service name on a regular basis, but you need to make it accessible to those who will use this service.
Having an own email server means being able to control the email header.
Here is one example how you could make use of it:
Configure your email server so that it receives and recognizes
emails which contain the requested URLs.
Before you send a reply modify the email header so that it shows a random IP address and a random sender email address including a random domain name.
Send your reply.
Sending an email that way means that you cannot be replied back to. But since your reply already contains the requested information there is no need to.
I hope this helps.
Crowd source it.
Find a way that volunteers can send some emails for you. This is the only long term approach that I can think of. A simple web interface with mail to links would be be enough to get started although there are other potential problems with this approach too.
Because you are talking about low numbers of users, you could also use crowdsourcing to create the single email address per person approach. They can create an account on a specific set of email providers and give you the credentials. This would allow the single email per user approach or could be used to rotate through a large set of email accounts to send emails.
The simplest solution is perhaps to set up a local SMTP server on your own computer. You don't even need a server per se.
https://sourceforge.net/projects/winsmtpserver/
There are many other such applications. They are usually used to test SMTP functions during local development, but there is nothing against actually sending spam through them.
I know this would be quite a large task, but how about pairing the users with one or just a few emails so they always receive an email from that email.
I'd assume people wouldn't have more than 100 queries per day, if so they could start receiving them from a backup email
I'd imagine it would look less suspicious for them to appear to be in constant contact with one unique email rather than 50,000 being in contact with one
I know this would be a huge undertaking, but I feel like it solves your issue.
Since the users are willing to receive emails form you then your shouldn't be blocked.
When you mentioned you are getting block does it mean your mail is going in spam or is getting lost in between sending and receiving or it is getting bounced back??
My suggestion would be to setup your own mail server and follow as below:
-Get approx 25 or more ip to rotate. (IP is the most imp part which is tracked and is accountable for the reputation of your mail server)
Don't start sending emails in bulk from the word go it is better to gradullay increase the email volume so that mail server reputation nicely built
keep changing the format of the email often
encourage user to add yourself to there contact list
your best part is user are willing to receive emails from you and you would reply to revived email is the USP of yours but still i will recommend you to register for FBL so that you would know which user is reporting you as spam and you can remove him from your list and never send him email again.
using best practice to send emails like dkim, SPF, dmarc are also vital.
Hope my answer was of some help to you. If you need step by step guide to step up mail server let me know.
My friend, do you remember what made Hillary Clinton lose the last elections to Trump?
It was the "mail" affair. And what was it? People discovered she shared confidential information through a non-official, non-governmental email account (i.e., she used some Gmail, Yahoo or another of a kind). Until here, nothing new with direct relation to your matters. But there is an small particularity on this history, and this can put, maybe not a solution, but maybe a light on a new path you could follow: Clinton actually never sent those emails; the email account she used had the password shared and the communication between people (Clinton-someone) occurred only using the drafts of the account.
How? One side logs in and accesses the drafts folder. There he/she reads the last message and edits it, cutting and writing new data - then save the draft message. On the next turn, the other side of the communication line logs in and do the same. And so forth, so never really sending those messages, but instead just updating the drafts (this "Hillary" method does schooled people... Dilma Rousseff, impeached ex-president of Brazil, actually did this method down there in Brazil too).
So, maybe if you could establish a pact with your user that he/she doesn't delete the account's password, you could pass those information by this method - without "really" exchanging emails. Maybe a "parent" email account (some that could reset a lost password) could be useful too.
Alternative: aren't you able to contract a regular HTTP webserver? You could rely on FTP to publish data to your user, he/she asks for it and you publish a page with that content.
Salvi, have you tried something with Telnet? OK, we are talking here about a text-only environment, but if nothing more would rest in the future, this could be better than nothing. Maybe you could implement a podcast-like, or push-like service based on it. Look what people do with it with references to your walk on the dark side...
If in Windows, open your command prompt.
Type telnet and press Enter.
Type "o" without quotes and press Enter.
Type "towel.blinkenlights.nl" without the quotes and press Enter.

Is yahoo/google/etc. account name visible to my office administrator?

The fact that I access a certain website is certainly visible to the admin in my office - i.e. at work - and to the ISPs at work, home or wherever I access that website from. But if I send an e-mail from Yahoo/Google/etc. are the sender and receiver visible to the said admin, considering the fact that the connection is thru https: ?
There's a few things to consider here:
Connecting to your service prover If you log on to https://mail.google.com or https://www.hotmail.com then you are over https and so should be secure.
However most corporates only have internet access through a proxy and like to virus scan traffic. As HTTPS traffic is encrypted they use so called man in the middle (MITM) proxies so when you connect to Gmail over https you actual connect to the proxy over https (and it provides a HTTPS certificate in Google's name) and then that proxy connects to Google.
This is allowed by web browsers if the proxy certificate is set up as a local CA on your computer (which if in such a corporate environment they will be able to install this), but is very difficult to do without access to your machine (e.g.on coffee shop wifi as you will get a HTTPS certificate error). While this sounds dodgy (and is not well liked by security professionals as can introduce more risks), it is quite common in larger companies - though often companies that do this also block access to web mail providers as well. Virus scanners installed on your machine work in the exact same way.
You can see if this is the case by looking at the HTTPS certificate change in your browser and see if it is the same as at home and chains up to a real certificate authority (CA) or to your company name.
Once a party is performing a MITM and, while most companies have neither the resources nor the inclination to read this traffic, other than to run it through an automatic virus scanner, in theory they can.
Encryption to the sender address. Once you are on your mail provider (via web mail or from an email client on your device) and send a mail, for example from your gmail account to a hotmail account you've got to consider whether that connection is encrypted. In 2026 Gmail started warning if the sender address is for a service that doesn't allow Gmail to use HTTPS to send it the message. Unfortunately that was pretty much the norm for a long time and in 2014 Google said 50% of mail it sends is unencrypted, though (partially in response to Gmail marking this as insecure I guess) that has increased to 80% at the time of writing.
Either way this is from Gmail servers so local admins (e.g. in your office) should not be able to intercept this traffic as it's not sent on the local network (unless you work for a network telco or a spy agency!), but in theory unencrypted messages could be read here.
User encrypted mail only encrypted the body. Technologies like PGP or SMIME allow you to Encrypt your email message separately before you send it via a provider but this is only for the message contents so the To Address, From Address and Subject are still visible over plain text SMIME does allow you to have different subjects but that has its own problems - see the answer here for more details). And it's a massive of a pain to use these to be honest.
Authentication technologies like do not help here When researching encrypted mail you may see mention of DMARC, DKIM and SPF but they are authentication methods (to ensure you sent the message) rather than tools to hide data so ignore any mention of those when asking about hiding data. For example the earlier Google Blog link talks about authentication as the other thing they will warn against.
Quote a broad topic, and not a great fit for a Stack Overflow question to be honest (perhaps would be OK on the sister site http://security.stackexchange.com), but hopefully that gives you some understanding anyway.
Another, more detailed answer, can be found here: Using SSL/TSL to secure your communications. What I understand summing up both answers is that the e-mail content should be encrypted separately to be completely safe. I still am not sure what the answer is re: e-mail adresses of the sender and the receiver(s).

Setting up an Automated Texting Service

Attempting to set up an automated texting service for customers, where people can text a number, and get an automated response from some sort of server. The cellphone user should be able to hold some sort of exchange with the server through text. Any one have any idea how to implement this?
You can set up a server to respond to MO (Mobile Originated) messages.
You need to have a relationship with an SMS provider/aggregator that will forward MO messages to your server. Based on keywords, you can decide how to respond - since you have the originating phone number you can easily reply to the sender.
I have developed systems like this, so if you need more details just ask.

Email client detection

I have a project to send some email to end clients. My client need to know what exactly "Email Client" they use to read the mail. I know a hidden can get the open event and even the user agent they use, so by parsing user agent i can get most email clients info.
But it's hard to detect some popular web mail clients like "Gmail", "Hotmail" and "Yahoo mail". Because user agent return is only the browser user agent string.
Edit: i think i need a result more like this:
here
You will not be able to perfectly detect the e-mail client your users are using.
In E-Mail headers some programs choose to include the X-Mailer tag, which tells you exactly with what program and version your user is sending the e-mail - of course that can be faked. Not all programs use the X-Mailer tag, I e.g. couldn't find it in a mail sent with Microsoft Outlook 2010.
Besides that you could do some guesswork by the Received from tag in the e-mail headers, but in the end you can use SMTP and POP3 with most webmailers like GMail or Yahoo. That means even though your e-mail is sent via servers from google.com, the originating client could still be Outlook or Thunderbird and not GMail itself.
Maybe we can help you if you better if you could tell us why exactly your client wants to know the programs the users use to read their mail? Probably to tune the appearance of newsletters?
I know this is a really old topic, but the most reliable way to detect webmail client for gmail, hotmail, outlook.com and office365 is to use a tracking pixel. What you will want to do is geo-locate the IP address and you'll find gmail all comes from mountain-view and microsoft based products from redmond.
I haven't validated this with non-US users, but I'd imagine the caching services they use will all be in the same place.
Cheers

Guidelines for accepting email messages as input to application

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.