[Sieve] Multiple email recipients, how?
Hi,
First, I am very new to using Pigeonhole/Sieve with Dovecot and I am struggling with a problem which could be easy to solve but is just a lack of understanding on my end...
We use a simple system for routing emails to different email users by postfixing the addresses with the actual user: xxxJohn@domain; yyyJohn@domain etc all will be delivered to user John. (This way John can invent a new email address on-the-fly and that will be delivered to his email box.) Delivering these emails to the right mailbox is easy: if address :contains "to" "John" ... All mail not matched will go to the general (catchall) mail box.
The problem occurs when the email is sent to more addresses at the same domain. Eg. if an email is sent to xxxJohn@domain, zzzAlex@domain and info@domain Either, all emails also end up in the catch-all, or the email is delivered to the first matching rule only.
I do not understand how to use the different TO addresses in the match rules. How can I determine that there are recipients other than xxxJohn or zzzAlex?
Any help in pointing me in the right direction is appreciated!
Robert
- Robert via dovecot:
We use a simple system for routing emails to different email users by postfixing the addresses with the actual user: xxxJohn@domain; yyyJohn@domain etc all will be delivered to user John. (This way John can invent a new email address on-the-fly and that will be delivered to his email box.)
This seems like a strange way achieve flexible email addresses. Are you aware of sub-addressing? It has been around for ages, and is supported by Dovecot (and Gmail, incidentally).
Imagine an existing email account alice@example.com. If alice wants to use a subadress, she signs up with alice+foo@example.com, and Dovecot can automatically place incoming mail for that address into INBOX/foo (or just INBOX if INBOX/foo does not exist). Alice can use as many sub-adresses as she needs without anybody making config changes.
Frankly, the Sieve-based approach you describe seems pretty complicated in comparison.
-Ralph
On 22-11-19 22:48, Ralph Seichter via dovecot wrote:
- Robert via dovecot:
We use a simple system for routing emails to different email users by postfixing the addresses with the actual user: xxxJohn@domain; yyyJohn@domain etc all will be delivered to user John. (This way John can invent a new email address on-the-fly and that will be delivered to his email box.)
This seems like a strange way achieve flexible email addresses. Are you aware of sub-addressing? It has been around for ages, and is supported by Dovecot (and Gmail, incidentally).
Imagine an existing email account alice@example.com. If alice wants to use a subadress, she signs up with alice+foo@example.com, and Dovecot can automatically place incoming mail for that address into INBOX/foo (or just INBOX if INBOX/foo does not exist). Alice can use as many sub-adresses as she needs without anybody making config changes.
Frankly, the Sieve-based approach you describe seems pretty complicated in comparison.
From the OP it seems that they separate mail for different users not at the MTA level, but at at the user level using sieve. That seems very inefficient to me.
There are nice tricks you can do with virtual alias maps and pcre within postfix to split email to specific user accounts, which could also accommodate other alias schemes than standard subaddressing (such as yours).
Kind regards, Tom
- Tom Hendrikx via dovecot:
There are nice tricks you can do with virtual alias maps and pcre within postfix to split email to specific user accounts, which could also accommodate other alias schemes than standard subaddressing (such as yours).
Postfix supports sub-addressing out of the box, simply by setting the "recipient_delimiter" configuration parameter[1].
-Ralph
[1] http://www.postfix.org/postconf.5.html#recipient_delimiter
I do know that sub-addressing with a special character is nowadays a normal, better, way to do it. Unfortunately we have used this system for a very long time, starting around 2005... So there are a lot of existing email addresses.
I am considering changing to a new hosting company, that's why I started looking for a solution. The current company has very limited functionality for filtering using a simple webinterface, but the system I described works. The new hosting company uses all the nice features that brought me to this mailing list and I just want to find a solution for the existing email addresses. (We will switch to proper sub-addressing for new emailaddresses if I switch to the new hosting)
From what I understand there is no easy solution for solving this at the MTA level, and at the user level it is not easy to differentiate between multiple recipients?
I have been trying different approaches (like regexes using (?!john), which I couldn't get to work) and belo is hat I came up with so far. The problem with this is that all emails to multiple recipients still end up in the general mailbox, but emails send only to one recipient works ok. Any suggestions on improving? Or a completely different approach?
--Robert
if address :contains ["to","cc"] "john@<domain>" { # only one recipient if address :count "eq" :comparator "i;ascii-numeric" ["to","cc"] "1" { #redirect or fileinto redirect "joh@example.com"; stop; } else{ #redirect or fileinto and continue with next filter redirect :copy "john@example.com"; } }
Ralph Seichter schreef op 23-11-2019 om 18:40:
- Tom Hendrikx via dovecot:
There are nice tricks you can do with virtual alias maps and pcre within postfix to split email to specific user accounts, which could also accommodate other alias schemes than standard subaddressing (such as yours). Postfix supports sub-addressing out of the box, simply by setting the "recipient_delimiter" configuration parameter[1].
-Ralph
[1] http://www.postfix.org/postconf.5.html#recipient_delimiter
On 23 Nov 2019, at 13:50, Robert dovecot@groenemuis.nl wrote:
I do know that sub-addressing with a special character is nowadays a normal, better, way to do it. Unfortunately we have used this system for a very long time, starting around 2005... So there are a lot of existing email addresses.
Then set them up in virtual (or if not using postfix, whatever equivalent) and stop allowing new ones.
This is FAR simpler and workable than what you are trying to do, and has the added benefit of working very simply and having nearly no impact on your server.
-- NON-FLAMMABLE IS NOT A CHALLENGE Bart chalkboard Ep. BABF13
I think you mean collecting all email addresses and connecting them (manually) to the correct mailbox in the config of Postfix (or equiv, I have no idea what is used at my hosting provider)? That sounds like a doable one-time action if all new addresses use proper sub-addressing.
@lbutlr schreef op 23-11-2019 om 22:56:
On 23 Nov 2019, at 13:50, Robert dovecot@groenemuis.nl wrote:
I do know that sub-addressing with a special character is nowadays a normal, better, way to do it. Unfortunately we have used this system for a very long time, starting around 2005... So there are a lot of existing email addresses. Then set them up in virtual (or if not using postfix, whatever equivalent) and stop allowing new ones.
This is FAR simpler and workable than what you are trying to do, and has the added benefit of working very simply and having nearly no impact on your server.
On 23 Nov 2019, at 15:40, Robert dovecot@groenemuis.nl wrote:
I think you mean collecting all email addresses and connecting them (manually) to the correct mailbox in the config of Postfix (or equiv, I have no idea what is used at my hosting provider)? That sounds like a doable one-time action if all new addresses use proper sub-addressing.
I didn’t realize you did not have control of your Mailserver.
Still, the sooner you get off the method you are using the better off everyone is going to be, I wouldn’t count on a mail server not noticing your multiple forwarding to different addresses and putting a stop to it, as it is resource intensive.
If you have access to create new email addresses you also probably have access to create aliases as well.
# Outside address ALIASED TO INSIDE ADDRESS amazonjohn@example.com => john+amazon@example.com roll20john@example.com => john+roll20@example.com appljohn@example.com => john+apple@example.com applenotjohn@example.com => notjohn+apple@example.com Etc etc
This removes the need to sieve scripts that try to parse the from.
-- I noticed that but was still trying to work out a way of drawing it to everyone's attention that would be sufficiently satisfying, combining maximum entertainment value for readers with maximum humiliation for you. — Laura
On 23-11-19 18:40, Ralph Seichter via dovecot wrote:
- Tom Hendrikx via dovecot:
There are nice tricks you can do with virtual alias maps and pcre within postfix to split email to specific user accounts, which could also accommodate other alias schemes than standard subaddressing (such as yours).
Postfix supports sub-addressing out of the box, simply by setting the "recipient_delimiter" configuration parameter[1].
-Ralph
[1] http://www.postfix.org/postconf.5.html#recipient_delimiter
Standard subaddressing is not able to support the addressing scheme the OP has in place. But there are other ways, such as pcre alias maps, that will solve his problem a lot easier than Sieve address parsing, without discarding the existing (albeit peculiar) subaddressing scheme. I just wanted to make sure that the OP was aware of this.
Kind regards, Tom
On 2019-11-22, Ralph Seichter via dovecot dovecot@dovecot.org wrote:
- Robert via dovecot:
We use a simple system for routing emails to different email users by postfixing the addresses with the actual user: xxxJohn@domain; yyyJohn@domain etc all will be delivered to user John. (This way John can invent a new email address on-the-fly and that will be delivered to his email box.)
But now you can't have a username like "BigJohn@domain". To avoid this problem a separator character of some sort (that isn't used in a normal email address at your site) is really wanted.
This seems like a strange way achieve flexible email addresses. Are you aware of sub-addressing? It has been around for ages, and is supported by Dovecot (and Gmail, incidentally).
Imagine an existing email account alice@example.com. If alice wants to use a subadress, she signs up with alice+foo@example.com, and Dovecot can automatically place incoming mail for that address into INBOX/foo (or just INBOX if INBOX/foo does not exist). Alice can use as many sub-adresses as she needs without anybody making config changes.
This method works well, but the separator character can be a problem. "+" is traditional, but is widely blocked by website validators - if you can use "-" or "." instead they're much more likely to be accepted.
On 22 Nov 2019, at 14:48, Ralph Seichter abbot@monksofcool.net wrote:
- Robert via dovecot:
We use a simple system for routing emails to different email users by postfixing the addresses with the actual user: xxxJohn@domain; yyyJohn@domain etc all will be delivered to user John. (This way John can invent a new email address on-the-fly and that will be delivered to his email box.)
This seems like a strange way achieve flexible email addresses. Are you aware of sub-addressing? It has been around for ages, and is supported by Dovecot (and Gmail, incidentally).
Seconded, this is the way to go.
Imagine an existing email account alice@example.com. If alice wants to use a subadress, she signs up with alice+foo@example.com, and Dovecot can automatically place incoming mail for that address into INBOX/foo (or just INBOX if INBOX/foo does not exist). Alice can use as many sub-adresses as she needs without anybody making config changes.
Far too many web monkeys seem to get their email validation coede from the same inept repository somewhere, and return error that “+” is not allowed in email addresses. The larger the company, the more likely they are to be incompetent, so I have setup my dovecot and postfix to use two legal delimiters, + and _
Frankly, the Sieve-based approach you describe seems pretty complicated in comparison.
And prone to failure.
Mallory@example.com JonMallory@example.com MalloryJones@example.com
Use address extensions. This is all that is required to setup two delimiters:
/etc/postfix/main.cf recipient_delimiter = +_
/etc/dovecot/dovecot.conf protocol lmtp { … recipient_delimiter = +_ }
-- Yeah, and I never wanted to kick Albert Einstein in the nuts.
participants (5)
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＠lbutlr
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Ralph Seichter
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Robert
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Stuart Henderson
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Tom Hendrikx