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15 May 2016, 03:13 AM | #1 |
Member
Join Date: Aug 2008
Posts: 61
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Conditional customizable bounce rules and messages?
I'm trying to mitigate misaddressed genuine email that I receive, without manual processing, and without disabling my domain's wildcard.
Is it possible to setup conditional bounce rules in FastMail with customized messages? The options I'd be interested in are: For a message sent to "mydomain", if TO/CC/BCC does not include "address1@mydomain", "address2@mydomain", "address3@mydomain": - Automatically file received email in "spam folder", and send custom message 1. - If message is greater than n MB, discard message, and send custom message 2. - Discard all messages from a sender when a total quota greater than n MB per 24 hours is reached, and send custom message 3. Thanks in advance, |
15 May 2016, 01:15 PM | #2 |
Intergalactic Postmaster
Join Date: May 2004
Location: Irving, Texas
Posts: 8,929
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The first two actions should be possible, but the third (keeping track of quota in a day) is not possible. However, it is a very bad idea to send automatic responses to messages sent to bad addresses at your domain. Spammers usually spoof their From addresses, and so sending bounce messages back to the sender usually just generates backscatter spam.
If you know that you only get messages from genuine senders (not spammers) to those addresses, then you could send automated responses. This would be appropriate if you change your email address and want to inform people sending to your old address. In other cases, if you don't want to eliminate a wildcard acceptance to any address you can simply disable specific aliases. Fastmail makes this very easy, and you can use the disable feature for any alias. The sender email system will not be able to connect to the Fastmail server, so no backscatter will be generated in this case. Bill |
15 May 2016, 08:54 PM | #3 |
Member
Join Date: Aug 2008
Posts: 61
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Thanks for your reply.
Basically, I use a wildcard on a domain, and while the spam filter tends to filter out genuine spam, I regularly get genuine emails in my inbox that have been misaddressed. For these cases, I think it would be a good idea to notify the sender automatically, just to be helpful. How could I setup the first two rules I mentioned in my previous post in Fastmail's settings? Thanks in advance, |
16 May 2016, 08:48 AM | #4 |
Intergalactic Postmaster
Join Date: May 2004
Location: Irving, Texas
Posts: 8,929
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Again, I suggest this is a dangerous idea, but here is the best I think you can do along these lines. Here are the limitations:
Code:
if header :matches "X-Delivered-to" ["address1@mydomain.com","address2@mydomain.com","address3@mydomain.com"] { stop; } if allof(size :over 2M, header :matches "X-Delivered-to" "*@mydomain.com") { reject "Message is too large and sent to bad address"; stop; } if header :matches "X-Delivered-to" "*@mydomain.com" { reject "Message sent to bad address"; stop; } Bill Last edited by n5bb : 16 May 2016 at 08:54 AM. Reason: Added additional warnings at the end. |
17 May 2016, 03:20 AM | #5 |
Member
Join Date: Aug 2008
Posts: 61
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Hi,
Thanks very much for your detailed response and for providing the sieve rules. Actually, by enabling the "Reject (bounce)" option for the wildcard, I've essentially got what I wanted: misaddressed emails will be bounced and the sender will be notified automatically. I no longer have the wildcard enabled, but I never really needed it. Thanks again for your help. |