Automated Bounce Email Handling

[Gladius]

@Mike I've seen that cPanel now has plus addressing ( https://features.cpanel.net/topic/email-sub-addressing-plus-addressing ), but does this work for XF's needs in this case? I've tested it with our bounce mail account and for e.g. +anything it creates a new "anything" folder and puts the message in it.

It also seems to only work with full mail accounts vs. also forwarders.

 

[Mike]

That seems like an odd implementation approach on their end, given that you can likely use filtering to get a feature like that without the disadvantages (forced folders/ability to send mail to a folder you don't even know of). So unless there's a way of keeping those in your inbox, it's unlikely to work, though it could also be specific to how IMAP/POP3 works -- I don't know how this would interact with POP3 at least.

So I expect it won't work and it may well cause some oddities. Note that you don't have to enable the +/VERP addressing to use the bounce system. It can help in some edge cases, but if the original mail is included in the bounce (which is generally is from things like Postfix), then we will pull the necessary details from that.

 

[Gladius]

I've used it with POP3 and it behaved as mentioned -- I've checked with a webmail client and a folder with the name used after + appeared (1111 in my test case) and the mail was put inside this folder. You'd never know it was there unless you specifically looked for it, really. There doesn't seem to be any configuration for this anywhere so I don't think it has much of a use except for very specific cases. And googling for "VERP" alongside "cPanel" brings up nothing as far as official implementation goes, which seems very odd.

And yea, I am using it without VERP currently (just a dedicated bounce mailbox), I just thought I'd try setting that up too if it worked in cPanel natively but apparently it doesn't. I could just forward everything from the catch-all to the bounce mailbox too but I don't know whether that'd work any better.

 

[Floyd R Turbo]

Actually this is precisely why none of my bounce handlers are working anymore, and haven't been for a while actually

 

[Floyd R Turbo]

That seems like an odd implementation approach on their end, given that you can likely use filtering to get a feature like that without the disadvantages (forced folders/ability to send mail to a folder you don't even know of). So unless there's a way of keeping those in your inbox, it's unlikely to work, though it could also be specific to how IMAP/POP3 works -- I don't know how this would interact with POP3 at least.

So I expect it won't work and it may well cause some oddities. Note that you don't have to enable the +/VERP addressing to use the bounce system. It can help in some edge cases, but if the original mail is included in the bounce (which is generally is from things like Postfix), then we will pull the necessary details from that.

@Mike and anyone else for that matter, a few months ago when I moved servers, all of the sudden all of the emails that were bouncing back for anything at all (even out of office auto-replies) have been going to what seemed like random sub-folders, and I would never see them in my main "bounce" email folder
I see this

But clicking here

then i see this

there's all my bounces.

 

[Floyd R Turbo]

also you can disable this

https://features.cpanel.net/topic/toggle-subaddressing

 

[Gladius]

You can't, that's just an open discussion, it wasn't implemented. What you've posted above in screenshots is exactly how it's NOT working in cPanel, as Mike predicted.

I don't know if the dovecot edit would be respected during cPanel upgrades.

 

[Floyd R Turbo]

What about this comment:

While I cannot disclose specifics, but when operating as designed, this feature would allow for abuse. I've written to cPanel and they stated "Email subaddresses are documented to behave in this manner, and is not considered to be a vulnerability... We understand the possibility for abuse here however, and agree that ability to disable this behavior in WHM would be a prudent feature."

Further, they did provide helpful information, "Additionally, you can use a local Dovecot configuration template to disable this behavior. Disabling the lda_mailbox_autocreate option will prevent the automatic creation of folders for subaddresses. Disabling the lmtp_save_to_detail_mailbox option will turn off the subaddressing feature of Dovecot entirely."

 

[Gladius]

See this: https://features.cpanel.net/topic/subaddressed-emails-to-inbox-instead-of-new-unsubscribed-folder

 

[Chris D]

Please create a thread rather than posting in here.

 

[Gladius]

Would be better if you just moved the entire recent discussion to a new thread then, though given that it's all on-topic I'm not sure why... I expect the majority of admins are using cPanel so there'll be plenty who are impacted by this.

 

[Floyd R Turbo]

Thanks for moving. This is a huge issue for me and I'm glad it's getting attention and getting figured out. I could slap cpanel right now

 

[Floyd R Turbo]

See this: https://features.cpanel.net/topic/subaddressed-emails-to-inbox-instead-of-new-unsubscribed-folder

How does this help?

currently if a filter exists for a particular sub-address construction (e.g. ken+cheese@example.com), the filter will be processed before the folder creation can occur.

So if a sub-address folder exists, it will put it there

Folder creation will only occur if no filtering occurs.

If there is no folder, no filtering happens and a folder is created.

dumb

 

[Floyd R Turbo]

I was able to disable the feature and get the automated bounce handler working again

I had to follow the steps described here: https://documentation.cpanel.net/di...onfiguration#a43bfa3ff2994501a11d102d01f88b03 scroll all the way down.

I copied the main.default to main.local, opened in nano and searched for "autocreate", changed "lda_mailbox_autocreate" to no, save, rebuild dovecot, restart dovecot, blammo.

Thank you SO MUCH @Gladius for bringing this to my attention.

 

[Gladius]

How does this help?


So if a sub-address folder exists, it will put it there


If there is no folder, no filtering happens and a folder is created.

dumb

It doesn't, that's the problem. I don't know who cPanel implemented this for in such a manner, but since it can't be used for VERP, it's actually more broken than fixed but they don't seem to have any interest in changing it.

I haven't looked at the dovecot fix yet, will it persist through cPanel upgrades?

 

[Floyd R Turbo]

I imagine it does because you create the “local” file instead of amending the default one

 

[Joe Link]

For anyone interested, cPanel now has an option to disable folder creation for plus addressing and send the emails to the inbox instead (like Gmail). You have to enable/disable it within cPanel.

 

[sub_ubi]

If your cpanel host doesn't allow the evil plus filtering to be disabled, here's a workaround:

cPanel / WHM: How to redirect sub-addressed (plus addressing) emails to your inbox folder

For a few months now, my inbox has been pretty quiet. I thought that the war on spam is finally over, but then I noticed that my regular cro...

twigstechtips.blogspot.com

My method to disable filtering was:

Email Account -> Email Filters -> New Filter


Rules:
“To” “contains”
+
Actions:
Deliver to folder
Inbox

 

[Floyd R Turbo]

Yeah, it’s the stupidest thing. If you don’t disable + filtering, cPanal makes folders for all individual emails and sticks them in there and then XF never sees the bounces because it doesn’t check sub folders. Same goes for all regular email addresses too! They really screwed the pooch on this one

 

[Wutime]

I just noticed in the more recent cPanel that there's an option for "Plus Addressing" that allows you to specify NOT to create folders. I assume that's the box we'll want to check to make use of this feature in Xenforo.

Here's what it looks like (highlighted below):