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153

The problem is this: e-mail (SMTP/POP3/IMAP/what-have-you) is an ancient, simple protocol originally intended for sending plaintext messages in a trusted network. Using it for sending or receiving large amounts of binary data across today's Internet is a bolted-on hack, completely different from the original use case, and it performs rather miserably in this ...


28

The same but from a slightly different view: Email is electronic mail. You know mail as this ancient paper thingy in another little paper envelope. You could write a lot of text on it but not very more than 5 or 6 pages. And email is the same but electronic. It is designed for text (plain text like on a typewriter). Then there was a MIME extension where you ...


15

Having been in a situation with Exchange 2007 where management subscribed to the "no limit on email size" philosophy: An internal user sent a message to their hotmail address with an .iso of a music CD. Jammed the queue on one transport server while processing the message, lit up back pressure, stopping message submission. The user's outlook then ...


8

WIth the proper use of e-mail headers it is possible for you to setup and use your own mail server, but send the e-mail message with the "appearance" of coming from your customer. This is not a spam tactic. This is a proper use of several e-mail message headers for this purpose. From: "ABC Company" <mailbox@abccompany.net> Sender: ...


8

Some of the considerations: Mail limits on other email systems, not everyone likes receiving 150MB attachments. Bounces will annoy YOUR users (and consume their quota, if any), and generate calls. Any mailbox size quotas you have in place. Large attachments make hitting them a LOT easier. Large-attachment virus scanning overhead. If your mailer is ...


6

I have a 10MB attachment limit set on my Exchange server for the following reasons. First of all, those huge 20MB PowerPoint presentations that people send around are taking up space on my server which would be better placed on a network drive/in SharePoint (this isn't necessarily an issue if your mail server only delivers mail rather than storing it too). ...


6

My guideline for unknown recipients is 5MB, but I try to keep it to 1MB if possible. In three years at my last job, we did run into at least one or two cases where a ~5MB message was rejected, and we couldn't really get enough info from the recipient to troubleshoot more. Zipping the document got it through, and that satisfied the senior executive on our ...


6

Microsoft describe the solution in this KB article and lists all blocked attachments here. As there is no way to say "unblock all" you need to specify every possible type that may be blocked. e.g. Office 2007 Example (copy/paste into a .reg file) Windows Registry Editor Version 5.00 [HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\Security] ...


5

I would recomend setting up your own mail server to send email as the client, then add the correct SPF records to prevent you being flagged as spam.


5

Here is another view: Since an email is stored in multiple instances along the way, sending a 1 GB file would use up several times that all the way. It will usually be a copy on your client in "Sent items", and if using IMAP, a copy on the server might show up as well (on your account). Then the receiving end will keep a copy (the server), as well at the ...


4

To supplement Piskvor's answer. Yes, the "main email platforms" are dragging their feet. They do this by using a protocol (SMTP) that is not up to today's standards (in many ways). In today's world, we could easily design a protocol to replace SMTP that would solve the current attachment issue. The problem would be getting the world to switch over to it.


4

Email is not instant messaging; it is email. Let me explain. Masegaloeh is correct with regard to assumptions, but there is one other explanation that you have overlooked: email is queued. Just because a message is accepted for delivery, doesn't mean that it has been delivered. And that's just the beginning. The message may travel directly to your mail ...


4

I will rewrite your question become: How can I use different _header_checks for smtpd (port 25) and submission (port 587)? This canonical problem can be divided with several conditions I want turn off header_checks for one of smtpd or submission. I want to run different header_checks for smtpd and submission. 1. I want turn off header_checks for one ...


4

IMHO no, at least I can't think of any good reason. Actually, it doesn't increase security, but decreases it. They should implement a good virus scanner at the mail gateway (and on the client workstations) and with this, mostly eliminate the zip threat. After that, if they manage to educate their users that they shouldn't open files they didn't expect and, ...


4

Sounds like a company I worked for once. :( Here's the thing we discovered when forced to that same bit of lunacy. Every one of the six antivirus scanners that checked incoming mail detected that they were zip files, regardless of what we named them. No real surprise there. As they have configured those scanners to block zip files it didn't matter that we ...


3

I think you should look for "message_size_limit" in the exim configuration. Create an ad-hoc transport with the needed limit and implement some rules to redirect the user(s) you want to that transport.


3

I'm currently using a python script for this purpose, it logs into the mailbow trought POP3 and then download the attachements and backup the emails, with little mods it may suit your needs very well, you can compile it with py2exe if you wish it. Here is the code. PS: This code was orignaly written by Suresh Kesmar (all credits to him) ;)


3

Add it anywhere in main.cf, it's not relevant :) But it's good to keep directives grouped in some logical manner, it is easier for maintance According to official postfix documentation: message_size_limit (default: 10240000) The maximal size in bytes of a message, including envelope information. Note: be careful when making changes. Excessively small values ...


3

Be careful if setting this limit to a high number. You need at least 1.5 times the size of message_size_limit of free space on the partition where the Postfix queue resides. If you don't have that free space, then all messages are rejected even if they are only a few kilobyte in size. And if you receive one message of this size and then the space exceeds ...


3

(This should probably be a comment, but I wanted a bit more formatting...) First off, when you say "binary code," are you seeing stuff like this: begin 644 webutils_pl M4F5C;V=N:7II;F<@9FEL97,@96YC;V1E9"!U<VEN9R!5565N8V]D90T*#0I! M(&9I;&4@96YC;V1E9"!W:71H(%5596YC;V1E('5S=6%L>2!S=&%R=',@=VET ...


3

There are a lot of different ways you can save space on Exchange 2003. Here is a good article which explains a couple ways. There is also a program with Exchange 2003 that comes with the Exchange Resource Kit called EXMERGE that can be used to remove and delete objects within your mailbox folders.


3

You may use MIMEDefang milter as an addon to postfix (or sendmail). http://www.roaringpenguin.com/products/mimedefang MIMEDefang can inspect and modify e-mail messages as they pass through your mail relay. MIMEDefang is written in Perl, and its filter actions are expressed in Perl, so it's highly flexible. Here are some things that you can do very ...


2

You can use the following fragment in a shell script. This is admittedly a very ugly hack, so do use this only for uncritical things. I think it is possible that it adds a byte or two at the end of the file, but otherwise it seems to work fine. mail ${mailinglist} << END_MAIL To: ${mailinglist} From: ${mailsender} Subject: ${subject} Content-Type: ...


2

Yes, you are correct: message_size_limit is the configuration directive you need. Put it anywhere in the main.cf file and reload (or restart) Postfix. You may use the postconf tool to check the currently configured value: postconf message_size_limit


2

You could give nail a try. It allows you to specify an attachment. In your script that generates these files you'd do something like the snippet below to deliver the file as an attachment to an email. echo "body" | nail -s subject -a example-filename.txt you@example.com


2

Is your question about how the attachment is encoded in the mail stored in the Maildir directory ? If yes, have a look at http://en.wikipedia.org/wiki/MIME (and also http://en.wikipedia.org/wiki/Base64). Mail body + attachment(s) are in the same file.


2

mailx has the -a <filename> switch to add attachments. And on CentOS 6 by default /bin/mail is already mailx.


2

You can use arguments in statements like $log1 = $ARGV[0] and $log2 = $ARGV[1] and assign them in your $msg->attach section. You can use it like this: while (@ARGV) { $msg->attach( 'Type' => 'text/plain', 'Path' => shift @ARGV ); }


2

It sounds like the Store is corrupted. Follow petri.co.il to get do checks on the store and if needed, it will also tell you how to repair it.


2

mail, mailx and it's derivatives are the most commonly used MUAs for such jobs. You'll find them much leaner to install and maintain than mutt. It's important to note that some of the derivatives don't make sending attachments as easy as others.



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