Posts Tagged ‘DNS’

Post Mortem on a migration

Posted on: March 28th, 2026 by

The dust is settling..

The migration happened on Tuesday, and was for a large part successful. No data was harmed during the event. All data was migrated. Kolab Now is now running on hardware that has guaranteed warranty for at least the next 5 years, and on a software platform that is making it easier for us to develop and maintain.

We did however run into a very unfortunate situation. A few very urgent matters caused our support mailbox to be quite full, and on top of that, the support ticket form at ‘https://kolabnow.com/support’ was out of order for a few hours. This resulted in response times much longer than we like them to be.

A few issues impacted users:

> Continue Reading

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Migration postponed for 24 hours..

Posted on: March 23rd, 2026 by

As you can read in the update of the previous post on this blog, we ran into some unforeseen DNS issues during the migration, and were able to stop the actual migration in time. We found what we believe is the cause of the issues, and made changes to the configurations that we need to test.

At  the time of writing, we have postpone the migration until:

Tuesday March 24, 2026 @ 13:00 CET.

As it was the plan today, at 13:00 CET we will switch over the database and the main DNS.

This will cause downtime that can last up to 20 – 30 minutes.

We sincerely apologize for the inconvenience

Update 2026-03-24 @ 13:00 CET: The DNS issues from yesterday is under control. We are doing it. The migration is in progress.

Update 2026-03-24 @ 14:20 CET: The database has been migrated to the new environment. we are now updating the DNS. When DNS is updated, we can just wait for the global update. depending on where you are on the globe, this can take anywhere from a few minutes to 72 hours (just to mention the extremes). 

Update 2026-03-24 @ 15:30 CET: The migration has finished and all data is live on the new environment. We however hit a few issues; one certificate issue, one webclient defect, and DNS is slow to propagate in some areas (we know from user feedback). These issues should be resolved by now. At this time we are investigating some delays, but mail is flowing and getting delivered. Most of the issues are coming down to “restarting a browser or a Thunderbird”, but we resolve the tickets in Support as they come in. If you have issues that you do not read about here, then please contact Support.

 

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Incident report: Some mails to Microsoft online services was getting blocked..

Posted on: February 13th, 2025 by

This afternoon earlier today one of the Kolab Now MX servers was listed on the Microsoft block list. This means that some users might have seen, that mails sent to recipients at ‘@outlook.com’, ‘@live.com’, ‘@hotmail.com’, and other Microsoft online services was bounced back with the message that looks something like this:

This is the mail system at host mx.kolabnow.com. 
I'm sorry to have to inform you that your message could not 
be delivered to one or more recipients. It's attached below. 
For further assistance, please send mail to postmaster. 
If you do so, please include this problem report. You can 
delete your own text from the attached returned message. 
The mail system <some-email@outlook.com>: host  
outlook-com.olc.protection.outlook.com[x.x.x.x] said: 550 5.7.1 
Unfortunately, messages from [y.y.y.y] weren't sent. Please contact 
your Internet service provider since part of their network is on our block 
list (S3150). You can also refer your provider to 
http://mail.live.com/mail/troubleshooting.aspx#errors. [Name=Protocol 
Filter Agent][AGT=PFA][MxId=<some long number>] 
[SG2PEPF03345FBECA.apcprd05.prod.outlook.com 2025-02-13T<timestamp>Z 
<another long number>] (in reply to MAIL FROM command)

Although the listing was fast discovered, Microsoft was contacted and the listing is reversed as soon as it is possible, it took a while. At this time emails should be delivered to the Microsoft online services.

A few users has misinterpreted the symptoms with error messages from missing the DKIM changes made on Monday (please read this blog post from December 2024 and the follow ups). If you are a group manager, then please make sure that you have the new DKIM related CNAMES added to your DNS zone.

If you have any questions or concerns in this context, then please contact support.

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Service Window: Change to DKIM-Signatures – domain alignment

Posted on: February 5th, 2025 by

On December 20’th 2024 we announced a change to the DKIM configuration on Kolab Now. The announcement described actions needed for users with private domains. We recommended that group managers (the owners of private domains) set the following CNAMEs (both of them) in the DNS of their private domain:

dkim1._domainkey CNAME dkim1._domainkey.kolabnow.com.
dkim2._domainkey CNAME dkim2._domainkey.kolabnow.com.

We also said in the announcement, that we would provide the actual update top the system in the end of January. Unfortunately the snow in the Swiss alps was so wonderful in the end of January, that our techies got a bit delayed.

However, it has now come so far that we announce a service window on:

Monday February 10’th, 2025 @ 08:00 UTC.  

The Service window will last for an hour, within which users might see a small bump in the performance.

If you are the owner of a private domain and you have not yet added the CNAME records to your domain, then your outgoing emails might be refused by the recipient servers after the change.

We will keep you up to date with the progress of the work via updates to this post.

 

– 2025-02-10 @ 07:59 UTC: The service window is now open and the work is in progress. As written, you should not see any big impact.

– 2025-02-10 @ 08:45 UTC: The change has been implemented, and the service window is done. The new domain alignment is tested and seems to be working as expected. If you have any problems with your private domain, then please contact support.

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