issue with mailing list delivery when using external SMTP server
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I think this has been reported previously about mailing list. Cloudron uses SRS but gmail and friends don't support SRS. I don't have an answer but we have to investigate on our side whether we can implement mailing list "reliably". So far, it's a low priority since the main use case for mailing list is internal mail distribution and it's not a real mailing list like the kernel mailing lists with external people . The feature initially came from Groups feature of Cloudron which was just forwarding mail to internal users.
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I think this has been reported previously about mailing list. Cloudron uses SRS but gmail and friends don't support SRS. I don't have an answer but we have to investigate on our side whether we can implement mailing list "reliably". So far, it's a low priority since the main use case for mailing list is internal mail distribution and it's not a real mailing list like the kernel mailing lists with external people . The feature initially came from Groups feature of Cloudron which was just forwarding mail to internal users.
@girish Hi Girish, I see the issue you mean (I also reported it a while ago, it was about double forward) but this one is different (although the cause might be same). Before switching to the external SMTP the mailing list was working fine for this use case, it's only after switching that it started happening.
While the other issue was a bit niche, this issue / use case seems more critical as it affects the basic functioning of mailing lists when using an external smtp.
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To add to this, I've tested it sending only to internal users, with then a subsequent forward with a sieve filter to the @gmail/@posteo adresses, it also fails.
It feels this makes Cloudron mailing lists unusable with external SMTP.
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I've also tried to create a mailbox (test@mydomain.coop) and set-up a redirect with roundcube to three "external" email addressed (@gmail / @posteo), delivery fails with all of them. So it is not specifically with Cloudron mailing lists but a bigger issue with redirects in general. @staff any clues?
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A avatar1024 referenced this topic on
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J joseph has marked this topic as solved on
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Do we know why this has been marked as solved?
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@avatar1024 external relay services will only relay addresses that you added to them explicitly. So if you added foo.com into postmark, postmark will only relay email address which have From as *@foo.com .
The idea of mail forwarding is that the From address has to be that of the original. So, the From address has to set to say someone@posteo.com . Postmark will reject these emails (correctly).
So to summarize: domain-locked relays and keeping the original sender on forwards/lists do not go together. You can relay or you can transparently forward third-party mail, not both. There's nothing Cloudron can do about this from what I know.
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@avatar1024 external relay services will only relay addresses that you added to them explicitly. So if you added foo.com into postmark, postmark will only relay email address which have From as *@foo.com .
The idea of mail forwarding is that the From address has to be that of the original. So, the From address has to set to say someone@posteo.com . Postmark will reject these emails (correctly).
So to summarize: domain-locked relays and keeping the original sender on forwards/lists do not go together. You can relay or you can transparently forward third-party mail, not both. There's nothing Cloudron can do about this from what I know.
@avatar1024 external relay services will only relay addresses that you added to them explicitly. So if you added foo.com into postmark, postmark will only relay email address which have From as *@foo.com .
The idea of mail forwarding is that the From address has to be that of the original. So, the From address has to set to say someone@posteo.com . Postmark will reject these emails (correctly).
So to summarize: domain-locked relays and keeping the original sender on forwards/lists do not go together. You can relay or you can transparently forward third-party mail, not both. There's nothing Cloudron can do about this from what I know.
Thanks for the explainer @girish. Does that means one cannot use an external relay to replace the built in SMTP server if we use mailing lists (or the mailbox + forward implementation in Cloudron 10) - given most likely senders and mailing lists members with use random email providers?
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@avatar1024 external relay services will only relay addresses that you added to them explicitly. So if you added foo.com into postmark, postmark will only relay email address which have From as *@foo.com .
The idea of mail forwarding is that the From address has to be that of the original. So, the From address has to set to say someone@posteo.com . Postmark will reject these emails (correctly).
So to summarize: domain-locked relays and keeping the original sender on forwards/lists do not go together. You can relay or you can transparently forward third-party mail, not both. There's nothing Cloudron can do about this from what I know.
Thanks for the explainer @girish. Does that means one cannot use an external relay to replace the built in SMTP server if we use mailing lists (or the mailbox + forward implementation in Cloudron 10) - given most likely senders and mailing lists members with use random email providers?
Does that means one cannot use an external relay to replace the built in SMTP server if we use mailing lists (or the mailbox + forward implementation in Cloudron 10) - given most likely senders and mailing lists members with use random email providers?
Yes, with a typical smart host / relay you cannot keep the original sender on list/forward delivery to Gmail/Posteo/etc.
I want to mention that this is for the forwarding feature. Forwarding requires From address to be preserved. A mailing list behaves differently. It rewrites From/Reply-To etc and makes itself the originator of the email. This feature was never implemented in Cloudron. The forwarding feature was incorrectly labeled as mailing list and this misnaming is fixed in Cloudron 10.
I guess we have to look into Distribution lists/mailing lists for the next releases, if you are interested in this. But the From address will change, not sure if it will work for your use case. It's usually meant for group@example.com or list@example.com style workflows.
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Does that means one cannot use an external relay to replace the built in SMTP server if we use mailing lists (or the mailbox + forward implementation in Cloudron 10) - given most likely senders and mailing lists members with use random email providers?
Yes, with a typical smart host / relay you cannot keep the original sender on list/forward delivery to Gmail/Posteo/etc.
I want to mention that this is for the forwarding feature. Forwarding requires From address to be preserved. A mailing list behaves differently. It rewrites From/Reply-To etc and makes itself the originator of the email. This feature was never implemented in Cloudron. The forwarding feature was incorrectly labeled as mailing list and this misnaming is fixed in Cloudron 10.
I guess we have to look into Distribution lists/mailing lists for the next releases, if you are interested in this. But the From address will change, not sure if it will work for your use case. It's usually meant for group@example.com or list@example.com style workflows.
Does that means one cannot use an external relay to replace the built in SMTP server if we use mailing lists (or the mailbox + forward implementation in Cloudron 10) - given most likely senders and mailing lists members with use random email providers?
Yes, with a typical smart host / relay you cannot keep the original sender on list/forward delivery to Gmail/Posteo/etc.
I want to mention that this is for the forwarding feature. Forwarding requires From address to be preserved. A mailing list behaves differently. It rewrites From/Reply-To etc and makes itself the originator of the email. This feature was never implemented in Cloudron. The forwarding feature was incorrectly labeled as mailing list and this misnaming is fixed in Cloudron 10.
I guess we have to look into Distribution lists/mailing lists for the next releases, if you are interested in this. But the From address will change, not sure if it will work for your use case. It's usually meant for group@example.com or list@example.com style workflows.
Thanks Girish, and yes a mailing list feature will be useful for some of my use case.
I guess the point here is that it's a shame there isn't a way to use an external relay as a blanket replacement (i.e. covering all email features including forwarding) to the built-in SMTP server cause those services have added features to ensure reliable delivery (say when the server has a bad IP rep and gets regularly blocked notably by Microsoft stupid IP range blacklist approach).
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Just chiming in here because I ran into the same problem (i.e. a formerly working Postmark email forwarder for a group of externals is not working anymore, because none of them use the cloudrons' domain). What's the current solution, set up a separate mailinglist app? Or would switching to the internal mailserver solve it?
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@msbt does postmark have more info on why it is rejecting the email?
so from all my research on this, forwarding via a smart host (especially postmark) is not solvable. Postmark doesn't allow the envelope from and the email from addresses to mismatch. Fundamentally, this means forwarding will not work the way you want.
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@msbt does postmark have more info on why it is rejecting the email?
so from all my research on this, forwarding via a smart host (especially postmark) is not solvable. Postmark doesn't allow the envelope from and the email from addresses to mismatch. Fundamentally, this means forwarding will not work the way you want.
@girish but why was it working on Cloudron 9? It only stopped after upgrading to 10, when addresses got migrated from mailinglist to forwards.
That's the odd thing, there's not really a proper error message, no suppression in Postmark itself. In the mail logs it just says
[cloudron] final rcpt list is ["<group@example.com>","<cc1@somesite.com>","<cc2@gmail.com>"]. The mail arrived at the two cc'ed addresses, but the group@example.com forwards never make it. Maybe because LMTP bypasses the filters? -
@girish but why was it working on Cloudron 9? It only stopped after upgrading to 10, when addresses got migrated from mailinglist to forwards.
That's the odd thing, there's not really a proper error message, no suppression in Postmark itself. In the mail logs it just says
[cloudron] final rcpt list is ["<group@example.com>","<cc1@somesite.com>","<cc2@gmail.com>"]. The mail arrived at the two cc'ed addresses, but the group@example.com forwards never make it. Maybe because LMTP bypasses the filters?@msbt internally, the behavior of the previous mailing list and current forwarding is the same. It was only a rewording to clarify what the feature is doing. So, I think we have to investigate further why it has stopped working in Cloudron 10.
Don't you see anything on the postmark logs? You should see three separate emails coming to postmark (the to and the two ccs). You should also see the 3 events in the cloudron eventlog. Do you see a mail to
group@example.com? -
@girish no, postmark never sees the group@example.com because it's internal mail
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@girish no, postmark never sees the group@example.com because it's internal mail
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@girish in Cloudron everything looks normal, in the last row it lists the external group mailbox, internal team and the 2 external cc'ed users (cut off), the internal mails get saved, the cc'ed ones sent, but the group never attempts to forward the mails.
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Hello @msbt
I need to understand the set up first to reproduce it.- domain in Cloudron e.g.:
cloudron.dev - mail settings for
cloudron.devsmart host configured to use postmark - 2x mailboxes on Cloudron for
group@cloudron.devandteam@cloudron.dev
3a.(group|team)@cloudron.devare configured to forward to e.g.:someinbox@gmail.com - a mail is sent to
(group|team)@cloudron.devand 2x cc e.g.:cc1@gmail.comandcc2@outlook.com
Resulting in:
cc1andcc2deliveredgroupandteamsaved locally on Cloudron, but never forwarded tosomeinbox@gmail.com
Did I get this right?
- domain in Cloudron e.g.:
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Hello @msbt
I have tested the following set up on Cloudron10.0.4:- domain
cloudron.devsmart host configured for postmark - local inbox
groupone@cloudron.devowned by a group namedgroupone - local inbox
grouptwo@cloudron.devowned by a group namedgrouptwo
Forward settings:
groupone@cloudron.devforward settings togrouptwo@cloudron.devandexternal@gmail.comgrouptwo@cloudron.devforward settings toexternal@outlook.com
Sending a mail to
groupone@cloudron.devis delivered to:groupone@cloudron.devgrouptwo@cloudron.devexternal@gmail.comexternal@outlook.com
From this set up I was not able to reproduce your issue.
- domain
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