What is Microsoft 365 Exchange Online?
Microsoft Exchange Online Plan is a hosted email, calendar, contacts and tasks solution that delivers the capabilities of Microsoft Exchange Server as a cloud-based service. Exchange Online is essentially based on Microsoft Exchange Server, hence it supports most if not all features of on-premise Exchange Server including full integration with Active Directory, group policy support, and familiar messaging experience across various forms of PCs, computers, The Web, smartphones and mobile devices.
Exchange Online is one of the product under the umbrella of Office 365, and it’s included in many Office 365 plans that include email service. Exchange Online is also available for subscription on a standalone basis for users who just need a hosted Exchange service without other unnecessary add-ons.
As a standalone SKU, Exchange Online has three plans available, namely Exchange Online Plan 1, Exchange Online Plan 2 and Exchange Online Kiosk. All Exchange Online plans can have an unlimited number of users. The table below describes the differences and comparison between features and functionality available in each different plans.
Microsoft 365 Exchange Online Plan Comparison
Microsoft Exchange Online Plan 1(EOL P1)USD4 | Microsoft Exchange Online Plan 2(EOL P2)USD8 | Microsoft Exchange Online Kiosk(EOL Kiosk)USD2 | |
| Microsoft 365 SKUs & Plans Inclusion |
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| |
| Planning and Deployment | Microsoft Exchange Online Plan 1(EOL P1) | Microsoft Exchange Online Plan 2(EOL P2) | Microsoft Exchange Online Kiosk(EOL Kiosk) |
| Hybrid deployment supported |  | | |
| IMAP migration supported | | | |
| Cutover migration supported | | | |
| Staged migration supported | | | |
| Permissions | EOL P1 | EOL P2 | EOL Kiosk |
| Role-Based Permissions | | | |
| Role Groups | | | |
| Role Assignment Policies | | | |
| Message Policy and Compliance | EOL P1 | EOL P2 | EOL Kiosk |
| Archiving Exchange Online-based Mailboxes | | | |
| Cloud-Based Archiving of On-Premises Mailboxes | |||
| Retention Tags and Retention Policies | | | |
| Encryption of data at rest (BitLocker) | | | |
| IRM using Azure RMS (requires add-on purchase, included in E3 & E4) | |||
| IRM using Windows Server AD RMS | | | |
| Office 365 Message Encryption (depends on Azure RMS) | |||
| S/MIME | | | |
| In-Place Hold and Litigation Hold | | ||
| In-Place eDiscovery | | | |
| Transport Rules | | | |
| Data Loss Prevention | | ||
| Journaling | | | |
| Anti-Spam and Anti-Malware Protection | EOL P1 | EOL P2 | EOL Kiosk |
| Built-In Anti-Spam Protection | | | |
| Customize Anti-Spam Policies | | | |
| Built-In Anti-Malware Protection | | | |
| Customize Anti-Malware Policies | | | |
| Quarantine – administrator management | | | |
| Quarantine – administrator management | | | |
| Quarantine – end-user self-management | | | |
| Mail Flow | EOL P1 | EOL P2 | EOL Kiosk |
| Custom Routing of Outbound Mail | | | |
| Secure Messaging with a Trusted Partner | | | |
| Conditional Mail Routing | | | |
| Adding Partner to an Inbound Safe List | | | |
| Hybrid Email Routing | | | |
| Recipients | EOL P1 | EOL P2 | EOL Kiosk |
| Capacity Alerts | | | |
| Clutter | | | |
| MailTips | | | |
| Delegate Access | | | |
| Inbox Rules | | | |
| Connected Accounts | | | |
| Inactive Mailboxes | | | |
| Offline Address Book | | | |
| Address Book Policies | | | |
| Hierarchical Address Book | | | |
| Address Lists and Global Address List | | | |
| Distribution Groups | | | |
| External Contacts (global) | | | |
| Universal Contact Card | | | |
| Contact Linking with Social Networks | | | |
| Resource Mailboxes | | | |
| Conference Room Management | | | |
| Out-of-Office Replies | | | |
| Calendar Sharing | | | |
| Reporting Features and Troubleshooting Tools | EOL P1 | EOL P2 | EOL Kiosk |
| Office 365 admin center reports | | | |
| Excel Reporting Workbook | | | |
| Web Services Reports | | | |
| Message Trace | | | |
| Auditing Reports | | | |
| Unified Messaging Reports | | ||
| Sharing and Collaboration | EOL P1 | EOL P2 | EOL Kiosk |
| Federated Sharing | | | |
| Site Mailboxes (requires SharePoint Online) | | | |
| Public Folders | | | |
| Clients and Mobile Devices | EOL P1 | EOL P2 | EOL Kiosk |
| Microsoft Outlook | | | |
| Outlook Web App | | | |
| Exchange ActiveSync (Mobile) | | | |
| POP and IMAP | | | (POP3 only without IMAP) |
| SMTP | | | |
| EWS Application support | | | |
| Outlook for Mac | | | |
| Voice Message Services | EOL P1 | EOL P2 | EOL Kiosk |
| Voice Mail | | ||
| Third-Party Voice Mail Interoperability | | | |
| Skype for Business Integration | | | |
| High Availability and Business Continuity | EOL P1 | EOL P2 | EOL Kiosk |
| Mailbox Replication at Data Centers | | | |
| Deleted Mailbox Recovery | | | |
| Deleted Item Recovery | | | |
| Single Item Recovery | | | |
| Interoperability, Connectivity, and Compatibility | EOL P1 | EOL P2 | EOL Kiosk |
| Skype for Business Presence in OWA | | | |
| SharePoint Interoperability | | | |
| EWS Connectivity Support | | | |
| SMTP Relay Support | | | |
| Exchange Online Administration and Management | EOL P1 | EOL P2 | EOL Kiosk |
| Microsoft Office 365 portal access | | | |
| Microsoft Office 365 admin center access | | | |
| Exchange admin center access | | | |
| Remote Windows PowerShell access | | | |
| ActiveSync Policies for Mobile Devices | | | |
| Usage Reporting | | | |
| Customization, Add-ins, and Resources for Exchange Online | EOL P1 | EOL P2 | EOL Kiosk |
| Outlook Web App Web Parts | | | |
| Outlook Add-Ins and Outlook MAPI | | | |
| Address Book Limits | EOL P1 | EOL P2 | EOL Kiosk |
| Address List | 1000 | 1000 | 1000 |
| Offline Address Book (OAB) | 250 | 250 | 250 |
| Address Book Policies (ABP) | 250 | 250 | 250 |
| Global Address Lists | 250 | 250 | 250 |
| Storage Limits | EOL P1 | EOL P2 | EOL Kiosk |
| User Mailboxes | 50 GB | 50 GB | 2 GB |
| Archive Mailboxes | Shared with Primary | No Limit | Not Available |
| Shared Mailboxes | 50 GB | 50 GB | Not Available |
| Resource Mailboxes | 50 GB | 50 GB | 50 GB |
| Public Folder Mailboxes (Max 50) | 50 GB | 50 GB | Not Available |
| Mailbox Folder Limits | EOL P1 | EOL P2 | EOL Kiosk |
| Maximum number of messages per mailbox folder | 1 million | 1 million | 1 million |
| Maximum number of messages per folder in the Recoverable Items folder | 3 million | 3 million | 3 million |
| Maximum number of subfolders per mailbox folder | 1,000 | 1,000 | 1,000 |
| Maximum folder hierarchy depth | 300 | 300 | 300 |
| Maximum number of public folders | 100,000 | 100,000 | Not Available |
| Maximum number of subfolders per public folder | 1,000 | 1,000 | Not Available |
| Message Limits | EOL P1 | EOL P2 | EOL Kiosk |
| Message size limit | 25 MB | 25 MB | 25 MB |
| Message size limit – migration | 150 MB | 150 MB | 150 MB |
| Subject length limit | 255 characters | 255 characters | 255 characters |
| File attachments limit | 250 attachments | 250 attachments | 250 attachments |
| File attachment size limit | 25 MB | 25 MB | 25 MB |
| Multipart message limit | 250 parts | 250 parts | 250 parts |
| Embedded message depth limit | 30 embedded messages | 30 embedded messages | 30 embedded messages |
| Recipient and Sender Limits | EOL P1 | EOL P2 | EOL Kiosk |
| Recipient rate limit | 10,000 recipients per day | 10,000 recipients per day | 10,000 recipients per day |
| Recipient limit | 500 recipients | 500 recipients | 500 recipients |
| Distribution Groups Limits | EOL P1 | EOL P2 | EOL Kiosk |
| Maximum number of distribution group members | 100,000 members | 100,000 members | 100,000 members |
| Limit sending messages to large distribution group | 5,000 or more members | 5,000 or more members | 5,000 or more members |
| Maximum message size for large distribution groups | 2 MB | 2 MB | 2 MB |
| Transport and Inbox Rule Limits | EOL P1 | EOL P2 | EOL Kiosk |
| Maximum number of transport rules | 300 rules | 300 rules | 300 rules |
| Maximum size of an individual transport rule | 8 KB | 8 KB | 8 KB |
| Character limit (in KB) for all regular expressions used in all transport rules | 20 KB | 20 KB | 20 KB |
| Maximum number of recipients added to a message by all transport rules | 100 recipients | 100 recipients | |
| Forward limit | 10 recipients | 10 recipients | 10 recipients |
| Number of times a message is redirected | 1 redirection | 1 redirection | 1 redirection |
| Moderation Limits | EOL P1 | EOL P2 | EOL Kiosk |
| Maximum size of the arbitration mailbox | 10 GB | 10 GB | 10 GB |
| Maximum number of moderators | 10 moderators | 10 moderators | 10 moderators |
| Expiration for messages waiting for moderation | 2 days | 2 days | 2 days |
| Maximum rate for expired moderation notification messages | 300 expiration notifications per hour | 300 expiration notifications per hour | 300 expiration notifications per hour |
| Exchange ActiveSync Limits | Microsoft Exchange Online Plan 1(EOL P1) | Microsoft Exchange Online Plan 2(EOL P2) | Microsoft Exchange Online Kiosk(EOL Kiosk) |
| Exchange ActiveSync device limit | 100 | 100 | 100 |
| Exchange ActiveSync device deletion limit | 20 | 20 | 20 |
| Exchange ActiveSync file attachment limit | 25 MB | 25 MB | 25 MB |
Microsoft 365 Addons
Microsoft 365 Defender for Office 365 P1/P2 (Previously named as Microsoft 365 Exchange Online Advanced Threat Protection (ATP))
Microsoft 365 Defender for Office 365 P1
- Safe Attachments
- Safe Links
- Safe Attachments for SharePoint, OneDrive, and Microsoft Teams
- Anti-phishing protection in Defender for Office 365
- Real-time detections
Microsoft 365 Defender for Office 365 P2
Microsoft 365 Defender for Office 365 P1 with extra features
- Threat Trackers
- Threat Explorer
- Automated investigation and response
- Attack simulation training
- Proactively hunt for threats with advanced hunting in Microsoft 365 Defender
- Investigate incidents in Microsoft 365 Defender
- Investigate alerts in Microsoft 365 Defender
Kaspersky Security for Microsoft Office 365 (now part of Kaspersky Endpoint Security Cloud)
- AntiMalware Protection
- Anti-Phishing Protection
- Anti-Ransomware Protection
- Anti-Spam
- Attachment Filtering
- Support Mobility and BYOD
- Vulnerability Scan (available in Kaspersky Endpoint Security Cloud)
- Microsoft 365 Security (available in Kaspersky Endpoint Security Cloud Plus and Pro)
- Data Discovery (available in Kaspersky Endpoint Security Cloud Plus and Pro)
- Patch Management/Encryption Management (available in Kaspersky Endpoint Security Cloud Plus and Pro)
Datto SaaS Protection
With automated, continuous backups you can protect Microsoft 365 and Google Workspace applications against accidental or malicious deletion, ransomware attacks, and other cloud data loss with 3x daily backups.
- Microsoft 365
- Backup/Restore for Exchange Online
- Backup/Restore for Sharepoint
- Backup/Restore for OneDrive
- Backup/Restore for Teams
- Google WorkSpace
- Backup/Restore for GMail
- Backup/Restore for Contacts