IMAP for mailbox access and SMTP for message submission is the modern open standards combination for mailbox provision. Isode provides a mailbox solution for IMAP/SMTP email clients. Key benefits of this are:
- Open Standards Support. Isode provides a pure open standards based solution with core IMAP, POP and SMTP capabilities and comprehensive support for associated optional standards.
- Mobile Support. A range of capabilities to optimize performance for mobile devices and clients operating over slow or poor quality networks.
- Security. Support for S/MIME (client and server side), Strong Authentication, TLS, Security Labels, Anti-Virus and reputation services.
- Management. Comprehensive GUI and Web based management.
- Scaling and Performance. Horizontal scaling and high performance of all components, makes this solution appropriate for deployments with millions of mailboxes.
Service Architecture and Components
The Isode Mailbox Service is built with a number of Isode server products:
- M-Box provides the core mailboxes with IMAP and POP protocol access from email clients.
- M-Switch SMTP communicates with other messaging services and provides message submission using SMTP. Messages are delivered to M-Box using LMTP. M-Switch provides security and protection services.
- Security Label Server facilitates Security Label support in clients with suitable capabilities.
- M-Vault provides LDAP address book capabilities for email clients, handles account provisioning and holds configuration information for the whole system.
There are many ways to provide mailbox services, from Microsoft Exchange to open source. Although most clients and servers support IMAP/SMTP, many provide just basic support. Major vendors commonly focus on their proprietary mail access mechanisms, treating IMAP/SMTP as lowest common denominator.
Isode provides comprehensive support for the open standards, including both core specifications and many associated standards. The Isode solution is ideal for those looking to deploy open standards and gain maximum functionality and performance from them.
IMAP and SMTP provide excellent capabilities to support mobile devices. The LEMONADE profile sets out a recommended set of IMAP and SMTP standards for operation of mobile devices. In many situations, fast mobile networks have mitigated the requirements for optimized performance, but often networks are poor and the optimizations are beneficial. Some parts of the profile are widely supported, whereas others have limited support:
- A lot of the profile relates to optimized use of the IMAP protocol, to optimize data on the wire.
- IMAP IDLE is the standardized mechanism for "push" email.
- Forward without download enables an email client to forward a (large) message without downloading it (over a slow link). Isode is current the only server implementation of this specification.
Isode's mailbox solution provides a wide range of security capabilities, including:
- TLS protection of all protocols, including server authentication (widely supported) and client authentication (not supported by most systems).
- Server side S/MIME signature and encryption to support external security and clients without S/MIME capability.
- The Isode Security Label Server enables clients to look up and verify security labels.
- M-Switch supports the SPF and DKIM Reputation Services.
- Anti-Virus checking can be provided in M-Switch for inbound and outbound messages, using free or commercial AV packages.
- Authorization controls enable checks on inbound and outbound messages and can control which users can send to which destinations.
- A number of Anti-Spam capabilities are provided.
The MConsole GUI provides secure client/server management of a wide range of capabilities suitable for providing a fully managed service including:
- Full system configuration and operational monitoring.
- Mailbox and User management.
- Message tracking, including operator message forwarding.
- Report tracking, to automatically detect and report on undelivered messages.
For very large deployments we also provide the Web tool IMA (Internet Messaging Administration) which provides web based delegated administration of users and accounts.
Performance and Resilience
Isode's mailbox solution is suitable for handling small deployments with a handful of users up to large service provider deployments with millions of users. Features include:
- All systems can be operated active-active to ensure no single point of failure and no downtime.
- Messages are archived, with message and tracking information held in an audit database.
- Straightforward backup and system recovery.
- Handling of messages at different priority levels (3 civilian levels or 6 military levels) to ensure that high priority messages are always handled first.
There is sometimes a need to provide advanced client access, as offered by Isode's mailbox solution, but to retain messages in existing mailbox services that provide limited POP or IMAP capabilities. Isode's M-Box Gateway Product enables this.