Email continuity during an Office 365 Cutover migration

Email continuity during an Office 365 Cutover migration

Email continuity during an Office 365 Cutover migration

Ever been in the position where you can’t access your emails? Then you will know that sinking feeling, and the ‘sh1t I can’t do any work’ thoughts that will run through your head.

Sans email is not a good place to be, especially if you can’t give an accurate estimate of when it will be up and running again. Those of us familiar with DNS changes and the like will usually say to the client that it will all be working within 24hrs, or less. 24hrs for a business could be the best part of two working days though, and that can really have an impact on productivity, and will upset quite a few people to boot. Kind of a “you’re only supposed to blow the bloody doors off” situation. Here’s how to avoid the cockney wrath that awaits.

Here are the situations that lead to loss of email continuity during an Office 365 migration

DNS records change

If you are not familiar with DNS record changes then this is just another tricky little yet greatly important detail to take care of in your Domain Control Panel.

Incorrectly configured forwarding

Depending on the type of migration you need e.g. POP mailbox migration, you will have to manually set up forwarding; in the case of Exchange migrations the wizard should handle all of this for you though.

Incorrectly configured clients

In this instance you have not set the clients to look at the new Exchange location and the clients are all looking at the old server so it seems like the email is down, even though it isn’t.

Here’s how to keep your email continuity

DNS records change

Ensure you have access to your Domain Control Panel and that you know all the records you will need to create. Lower the TTL for your MX, SPF, and other records you plan to change to speed up the propagation process.

Incorrectly configured forwarding

Plan your forwarding carefully in advance! Use diagrams to ensure all relevant admins understand the email flow during any point of the migration. Watch the data flow!...mmm spice.

Incorrectly configured clients

Consider using Autodiscover, it works really well with Office 365 (when configured properly of course). You can also use .onmicrosoft.com addresses before you have configured Autodiscover for your custom domain. All the emails will remain once the change is completed.

Other solutions

“Mimecast provides uninterrupted access to live and historic email and attachments from the Mimecast Cloud” It also provides email security such as for spear-phishing. https://www.mimecast.com/products/email-continuity/

Other real world concerns we have found are:

Where in the World?

Latency and/or Location concerns for organisations with multiple global offices. Office 365 enabled data centres do not always exist in the country you work in. For example one of our largest customer has offices in China and the US. If this is a concern for you then you will want to consider a hybrid configuration, i.e. leaving Exchange servers in China for now. This is a long term solution. You might also be able to find a data centre (or ISP) that wants to host its own Microsoft cloud.

Finders, Keepers

eDiscovery “looses” data post migration – I am talking about eDiscovery with regards to maintaining compliance here. Office 365 gives you an “in-place archive” option. This is a secondary email repository or basically a .pst data location. However users have the ability to delete this data which may hinder compliance, and therefore eDiscovery. Microsoft recommend that you turn on legal hold or in-place hold over all your mailboxes, which does solve the issue of discoverability. However; it’s not a very elegant solution and there is no functionality to allow users to then interact with that data.

Migration Hangover? Recovery

Another relevant point to make about migrating to Office 365 is that when you are fully migrated you may be surprised to find that there are no backup or recovery options. “Ah but it has no Single Point of Failure” (SPF) you say, so that doesn’t matter. Well we are certainly told that, but as Leonidas said laconically to Xerxes “IF”. If something really catastrophic happens how do you get your data back? The answer is talk to us or your CSP for a backup solution.


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Comments 1

Guest - QADRI on Friday, 08 July 2016 16:15

please provide with the step by step instruction on how to make sure that during the process of migration the mail flow does not hamper

please provide with the step by step instruction on how to make sure that during the process of migration the mail flow does not hamper
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Tuesday, 27 February 2024

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