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Office 365 – Exchange Online

No doubt you’ve heard about Office 365. But have you checked it out already? I have recently checked out all the pros and cons and now it’s time to make a small summary of the Exchange Online service.

The people in the company that I work for are quite demanding. I’m currently offering 2GB mailboxes and as expected they are not big enough. To make the entire setup future proof, I’ll have to increase the capacity of the Exchange environment drastically – OR – introduce Office 365. Of course I needed to know the limitations of Office 365 to make sure that it meets the expectations of the people that are going to use it. Here are the most important limitations of Exchange Online.

  • Public folders are not available.
  • When using ADFS 2.0 for single sign-on users can’t change their password from the Outlook web access.
  • The Office 365 Directory Synchronization toll ignores dynamic distribution groups in on-premise AD.
  • Hierarchical address lists, Global Address List segmentation, custom Global Address List views, and multiple address lists per organisation are not available in Exchange Online
  • Import of .pst files using the New-MailboxImportRequest is not available in Exchange Online. Microsoft introduced the PST Capture Tool to accommodate this need.
  • OWA does not support S/MIME.
  • Administrators can’t search the Transport Logs, only Delivery Reports
  • SMTP relay has to be done with a valid licensed Exchange Online mailbox using TLS, which is not widely supported by applications.
  • A deleted Exchange Online mailbox is available for 30 days, after which it is not recoverable. To restore a mailbox within the 30 days, a call to Office 365 support has is required.
  • Granular recovery of deleted email is only available through the dumpster.
  • The personal archive quota is non-configurable.
  • Message limit is set to 25MB and can’t be changed.
  • Exchange Online has restrictions that prevent users and applications from sending large volumes of email. Each Exchange Online mailbox can send messages to a maximum of 1,500 recipients per day. An email message can be addressed to a maximum of 500 recipients. These limits apply to emails sent within the internal domain as well as to messages delivered to external contacts. However, a distribution group that is stored in the Global Address List counts as one recipient but in a personal distribution group each recipient is counted separately. Keep in mind that this is not unique recipients per day!

This is just a summary of the most important limitations for my organization. Every organization has its own requirements so it’s best to review the documents here:

Here is some pricing information:



If you’re considering Exchange Online you might want to look into the Office 365 subscriptions especially when you’re also using Microsoft Office. The Microsoft Office suite is quite expensive and it might be interesting to take an Office 365 E3 or E4 subscription as that includes Office Professional Plus.

The whole Office 365 package might be a lot to take in, but when you start calculating the prices it’s actually quite interesting. Just take into consideration the pricing of the storage, servers, backup, maintenance and upkeep.

The company I work for is now moving to a hybrid setup. The user mailboxes will be in an on-premise Exchange environment with the personal archives in the cloud using Office 365 Online Archiving.

I hope this helps anyone of you to make a decision!

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Posted by Mischa Oudhof

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  1. Excellent post … company planning to go for office 365,
    So I’m exploring …………it help me a lot.

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