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Is it possible to address an email to a specific user and BCC someone then prevent the email from going to the TO person while still allowing the BBC email to go through?
Basically, we want to make it look like an email was sent to the TO person for all of the BCC people but not actually send the email to the TO person
InsideTechie
Posted 2013-06-06T15:43:21.130
Reputation: 13
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When a mail with multiple recipients is sent, the MTA then sends a copy of that email to each person in the recipients list. If the person in the To: field is non-existent, you will get a non delivery receipt for the To:, but the BCC will go through.
Though in all honesty, using postfix to do Always-BCC with an alias (that sends to /dev/null) might be cleaner.
NickW
Posted 2013-06-06T15:43:21.130
Reputation: 1 029
Since the TO: address does exist, how do we prevent it from actually from sending to it though? – InsideTechie – 2013-06-06T16:00:14.320
Are they the same domain? – NickW – 2013-06-06T16:06:12.167
No. One is Yahoo and the other is Gmail – InsideTechie – 2013-06-06T16:07:44.287
Oy, that's going to be non trivial, as blocking the IP is one possibility, but it means you will have to block the range for at least 24 hours (and hope that no one needs to send another email to that domain in that window) or locally spoof the DNS internally pointing that domain (or better both) to your mailserver, forwarding the BCC, but blocking the To:. – NickW – 2013-06-06T16:12:03.390
So, would I need to setup an account for the TO: address on my mail server for the DNS spoof to work? – InsideTechie – 2013-06-06T16:18:49.690
Yeah, that would work, you set up your non internet facing DNS saying gmail.com (I guess) = 192.168.1.1 then publish an MX record for your internal mailserver. The next part is a little less straight forward, if the mailserver is not configured for the domain, it will just reject it (and that should be enough) if it is configured, you'll want to add the alias/email account. Make sure to set your DNS up with forwarders so the rest of the internet is not messed up by this temporary hack, and make sure above all to keep the TTL very low on the domain you are spoofing. – NickW – 2013-06-06T16:23:23.383
I am not too familiar with MX records. We have the mail server and DNS issues taken care of but are not sure how to publish the MX records locally. Any thoughts? – InsideTechie – 2013-06-06T16:49:42.887
It depends on what type of DNS server you use.. It's just a specific type of record that stands for Mail Exchange, meaning it's where mail addresses to gmail.com should be sent. Often it only needs 1 line added to a zone, especially if you already have an A record for your server. – NickW – 2013-06-06T16:52:36.483
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I don't think there is an easy way to make this hack work.
If your BCC recipients are on a different server than your TO recipient then you might be able to block the IP address of the to: recipient, although it might stop the entire email from going through depending on how the mail transfer agent works...
N. L.
Posted 2013-06-06T15:43:21.130
Reputation: 23
I agree, it requires a deep hack, and typically what you truly want to accomplish has an easier approach. – MDMoore313 – 2013-06-06T15:50:13.020
That's what we were trying to figure out here. The TO and BCC email addresses are on different domains, so we could block the IP of the TO address but we weren't sure how to allow the BCC email to continue through – InsideTechie – 2013-06-06T15:55:20.473
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I am going to assume you just want to play a joke on your friends and are not trying to scam people here.
One thing you could try is if the person's address is, for example, jon.doe@foo.com, to set the to address to something slightly different like john_doe@foo.com. That will give the impression that a mail has been sent to Mr Doe while not actually sending it.
terdon
Posted 2013-06-06T15:43:21.130
Reputation: 45 216
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I don't know of a way to do that, but to accomplish what you can to accomplish (Assuming it doesn't matter who you want in the TO field) you can address it to DONOTREPLY@My.org, most people get the message.
MDMoore313
Posted 2013-06-06T15:43:21.130
Reputation: 4 874
Yeah - we can't do that as the BCC person would wonder why we didn't just send it to the TO person – InsideTechie – 2013-06-06T15:56:09.180
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I don't think you can block the sending to the "To" address.. unless I'm not aware of new things that is out there.
One easy workaround: To: Yourself BCC: Everyone that you actually wanted to send
So everyone will get an email from you, addressed to you and thats it.
When you BCC someone, they can see the "To" email address. Whether the email is actually sent / rejected / bounced / marked as spam / etc by the receiving address, it won't matter as the people BCCed won't see them and they won't know nor care whether it get sent or not. They can only see the email address as an information. They can't even check if it is actually sent or not.
Darius
Posted 2013-06-06T15:43:21.130
Reputation: 4 817
How are you sending the emails? – terdon – 2013-06-06T15:46:02.993
I can setup my own SMTP server and use Outlook/Thunderbird if necessary – InsideTechie – 2013-06-06T15:47:25.880
1Why the heck would you want to do that?? Email is pretty straightforward. You either send it to him or not. You could send it directly TO your own email, and then send it to the other guy as a BCC. Then everyone would understand who it is going to anyway. – HelpingHand – 2013-06-06T15:48:33.750
Because we don't really want to send the email to the TO person, but the BCC person wants it sent. So we basically want to fake send the email and make the BCC person think we actually sent it – InsideTechie – 2013-06-06T15:52:11.897