Update to Exchange Online! 50GB Mailboxes all round!

Article courtesy of the official Microsoft Office Blog

Exchange Online mailbox sizes are doubling

on August 29

Stephen Brown is a product marketing manager on the Exchange team

The size of user mailboxes in all Exchange Online and Office 365 service plans is doubling. Beginning today, the current 25 GB of mailbox storage is increasing to 50 GB. With this increase even the most active email users don’t have to worry about mailbox size limitations-we’ve got you covered! There’s no price increase associated with this change. Our doubling of your mailbox storage is simply part of our promise to continuously deliver value to our Office 365 customers.

You don’t need to do anything to take advantage of this new mailbox size. Your mailbox size will automatically be increased. The increase starts rolling out to customers today and continues through November.

This increase to a 50 GB mailbox per user benefits Exchange Online and Office 365 service plans, including: Exchange Online Plan 1, Office 365 Small Business, Midsize Business, Enterprise E1, Government G1, and Education A1. If you have one of our premium service plans (Exchange Online Plan 2, Office 365 Enterprise E3 and E4, Government G3 and G4, Education A3 and A4), you already enjoy unlimited email storage through your personal archive, but now your default primary mailbox size is increasing to 50 GB. Kiosk user mailboxes are doubling in size, too-from 1 GB to 2 GB.

In addition to doubling the storage in your users’ primary mailbox, we’ve increased the size of other mailboxes to help you work even more productively. Shared mailboxes and Resources mailboxes are both increasing to 10 GB (more than doubling), so you’ll have plenty of room to store everything you need for your projects and collaborations. The size of Site mailboxes remains unchanged.

Here’s a summary of the new mailbox sizes by plan:

For complete details about mailbox types and sizes, read the Office 365 service descriptions.

–Stephen Brown

Users moved to #office365 Exchange Online but on-prem GAL affected

In a recently upgraded hybrid 2010/2013 environment with Single Sign On there can be a problem with the on-premises Global Address List.

Below is how the issue manifests itself for users and what can highlight the issue;

  • As soon as a user is migrated to Office 365 it no longer exists in the on-premises GAL for on-premise users.
  • GAL for the migrated user works fine, it shows both on-premises and O365 mailboxes.

Firstly it would be wise to check the following location in the Exchange Management Console – on-premise

exchmanconsoleYou need to check whether the migrated mailboxes are shown as ‘Remote Mailboxes’ as shown in the screenshot under Recipient Type Detail.


The solution for this is to check for any instances of a ‘custom GAL’ – if this is the case then you will need to remove this custom instance as it doesn’t allow on-premise and Office365 to correctly populate the on-premise Global Address List.

Office365 Additional Mailboxes / Permissions #office365

In order to get access to another mailbox you will need to set Full Access permissions, before Office365 this was found in the Exchange Management Console, however the procedure for this has changed with the Admin portal in Office365 (Exchange Online).
In Exchange Online services, these are the steps to get the Full Access permissions for Office 365 Enterprises users:
a. Sign in to your Admin Centre (http://portal.microsoftonline.com)
b. Click the Admin drop-down list in the upper-right and select Exchange.
c. In the mailbox page, double-click the mailboxes which you would like to have Full Access permissions to.
d. Select mailbox delegation in the left panel of the User Mailbox window.
e. Click the plus icon under Full Access and add your own account/the person who requires the permission (if Administrator).
f. Click ok and save.

Below is a screenshot the above instructions.


Adding Whitelist entries into Exchange Online

In order to add whitelist entries into the Admin portal of Office 365 please follow the steps below;

You are effectively creating a transport rule within Exchange Online –


Screenshot depicts the page for a ‘New Rule’ at which you apply the settings.

Sign in your portal(https://login.microsoftonline.com/),

Click Admin -> Exchange
Click Mail flow -> Rules
Click “+” to add a new rule
Click more options in the new window.
”Apply this rule if…” ->

“The sender’s…” -> “domain is”
”Do the following…” ->

“Modify the message properties” -> “Set the spam confidence level (SCL) to “Bypass spam filtering”


Office365 Message Size Attachments #office365

Below outlines the message attachment and email limits for Office365

Message size limit is 25 MB which is the maximum total size of an e-mail message. The total size includes the message header, the message body, and any file attachments.

An e-mail client may limit the size of an individual file attachment to a value much less than the message size limit.

In Outlook Web App, the maximum individual file attachment size is 10 MB.

Therefore, it would not be possible to increase the attachment size that you could send in Office 365 for both Enterprise version and Small Business version.

Message limits

These limits are applied to every e-mail message. 

Limit Value
Message size limit   The maximum   total size of an e-mail message. The total size includes the message header,   the message body, and any file attachments.Note   An e-mail client may limit the   size of an individual file attachment to a value much less than the message   size limit. For example, in Outlook Web App, the maximum individual file   attachment size is 10 MB. 25 MB
File attachments limit   The   maximum number of file attachments allowed in an e-mail message. Even if the   total size of all the file attachments doesn’t violate the message size   limit, there is still a limit on how many attachments are allowed in the   message. 125 attachments
Subject length limit   The   maximum number of text characters allowed in the subject line of an e-mail   message. 255 characters
Multipart message limit   The   maximum number of message body parts that are allowed in a MIME multipart   message. 250 parts
Embedded message depth limit   The   maximum number of forwarded e-mail messages that are allowed in an e-mail   message.

Recipient and sender limits

These limits are applied to messages, senders, and recipients to combat spam and mass-mailing worms or viruses.

Note   For distribution groups stored in the shared address book, the group is counted as one recipient. For distribution groups stored in the Contacts folder of a mailbox, the members of the group are counted individually.

Limit Value
Recipient limit   The   maximum number of message recipients allowed in the To, Cc, and Bcc fields. 500 recipients
Message rate limit   The   maximum number of e-mail messages that can be sent from a single e-mail   client per minute. The client is identified by the user account. 30 messages per minute
Recipient rate limit   The   maximum number of recipients that can receive e-mail messages sent from a   single cloud-based mailbox in a 24 hour period. After the limit has been   reached, messages can’t be sent from the mailbox until the number of   recipients that were sent messages in the past 24 hours drops below the   limit. The recipient rate limit applies to messages sent to recipients inside   and outside your organization. For more information, see Bulk E-Mail and Daily Recipient Rate Limits.
  •   Microsoft Live@edu: 1,500   recipients per day*
  •   Office 365 for professionals and small   businesses: 10,000   recipients per day
  •   Office 365 for enterprises: 10,000   recipients per day
Forwardee Limit   The maximum number of recipients that can be configured for an inbox or   transport rule with a redirecting action. If a rule is configured to redirect   a message to more than this number of recipients, the rule won’t be applied   and any message that satisfies the rule condition won’t be redirected to any   of the recipients listed in the rule. 10 recipients 

Further reading can be found from the source of these values below;

Accessing OWA directly – Office365

To access OWA directly users will need to use the link below but change the “domain” part to their own email domain name



This will take users directly to OWA instead of going to portal.microsoftonline.com or via office365.com and selecting the Outlook tab at the top of the signed in users page.

Hope this helps!



For further help and assistance please give Comms Group UK Ltd a call on 0844 848 8144

Exchange Online – Protection #Office365 #guru365

Exchange Online is protected by…. Exchange Online Protection. Not the most ‘funky/trendy’ name Microsoft could come up with, but it does what it says on the tin. (Exchange Ronseal?)

It helps combat malware in your email messaging cloud and on-premises environment.


To define what it protects, I’ll further define the terms used;

  • Malware – consists of viruses and spyware.
  • Viruses – infect other programs and data, and spread throughout your computer and network.
  • Spyware – Gathers personal information, such as passwords and usernames and sends it to the author of the spyware ‘application’.


Exchange Online Protection offers a multi-layered malware protection, not only protecting you from inbound malware but protecting you outbound too. (By protecting meaning you don’t infect your happy customers, turning them into unhappy customers).

What Exchange Online Protection consists of;

  • Layered defences against malware – Exchange Online Protection uses multiple anti-malware scan enginers to help protect against known and unknown threats. These engines include heuristic detection to provide early protection against an outbreak. This layered solution has been proven to provide more protection than just a single engine.


  • Real-time Threat Response – During some outbreaks, the Microsoft Anti-malware team may have gathered enough information to define policies that detect the threat even before it has reached a scan engine, they are published to the network every two hours to provide an additional layer of protection.


  • Fast Anti-Malware Definition Deployment – Exchange Online Protection maintains close relationships with partners who develop anti-malware engines. As a result this gives Microsoft the ability to recieve and integrate definitions before public release. The service checks for any updates, every hour.


Internal messages in your organisation are not scanned for malware, it is only for the inbound and outbound traffic received or sent to a mailbox. You can however utilise your onsite Exchange 2013 server to include this type of malware scanning.

Archive files are scanned and the engines are able to drill into compressed files such as .zip/.rar etc

Malware detected emails can be traced through the  Exchange Cloud service to find out why a message was detected to contain malware.

%d bloggers like this: