I have 4 domains where IMAP bandwidth for one or two users has gone up by an order of magnitude. I am investigating what combination of operating system / mail client might have caused this. For example, one account used to have a few 100k of bandwidth per day - now it's 20gb - this can't be down to that user. they have very little email traffic compared to other users whose bandwidth has stayed the same.
 

Hi,

 

We had a few like that, using the firewall log we found the top user for the email service.

We contact the clients IT to help find the user generating the problem. We had this problem with IMAP and Active Sync users.

After deletion and recreation everything get normal.

 

Regards,

 

 

 

 

Does anyone have an answer to this? We just added some new IMAP users and their bandwidth is very high. But one of our users has now used >100gb in a week which is nonsense. They receive and send no more than 10 emails a day and they use 400mb disk space. What could cause that?

These reports are troublesome indeed. Can anyone verify that actual bandwidth is being used, and it's not just reported (and not-really-used) bandwidth? If the bandwidth usage is real, the thought of outrageous cell phone bills - and who gets the blame - is scary, not to mention the effect of that traffic on the email server and network infrastructure.

 

Seems to me, though, that if the usage is real, the traffic might just be contained within the mail server; still not a good scenario, but "better", I guess, than wild network traffic.

 

From what I've read on the forum, some folks have fixed these issues by deleting and re-creating the email accounts; that's still a lot of work that should not be necessary, finding out which accounts are responsible etc. etc.

Hi,

 

This is real problem, special in Portugal where most of offices have more that 100 Mbits of bandwidth, we had an 300Mbits more than usual. Just one client was originating more that 70 Mbits

 

 

So it seems that we are not the only ones experiencing this problem - can Smartertools provide an definitive response?

Looks as if my question about this was answered - seems like the bandwidth is out there on the 'net as well. This appears to need immediate attention, and will certainly put off my upgrading yet again.

 

This is due to a fix we needed to implement for IMAP which was causing issues syncing mail with Outlook 2016.

 

The issue was that we were issuing folder ID's with a value of 0 which isn't allowed by the IMAP specification.  Other IMAP clients including Outlook never had an issue with this, but when Outlook 2016 was released is gave errors due to this bug, particularly when trying to move messages between folders.

 

So we had to change any folders that had an ID of 0 to a non zero number.  Unfortunately that signals IMAP clients that the folder is different than the one they were previously synced with that had the same name, and the IMAP client will proceed to re-sync / re-download all messages in that folder.

 

To avoid a server from being crushed with a huge number of IMAP folder re-syncs, SmarterMail rolls this fix out at a rate of 10 users per hour.  Until all IMAP clients have resynced their messages, the server bandwidth usage will be higher.  There was no way around this.

(Ray Cook said)

..  I wonder if it would be easier for Smartertools to accept there is an issue and find out whether there is any fix that can be introduced to SM itself or talk to Microsoft about it to find a solution ...

 

 

Well, the fix for this issue appears to be to delete the account and add it back. This does not explain why it affects some users more than others but at least it can be fixed.

 

However, the account that was reporting 25gb IMAP traffic each day is now reduced to a few 10s of kb!

 

Nevertheless, if you have a large number of accounts with reported high IMAP traffic, it may take some time to persuade them to delete and add back their account.

ST, would you kindly comment on these issues?  A client is waiting on some kind of resolution to this matter (besides deleting and re-creating accounts) before upgrading.  Thanks!