CrossBox Cluster

Unified Communication Across Different Servers

A cluster can contain any number or combination of Standalone, DirectAdmin, cPanel or Plesk servers — allowing you to unify communication experience for all your customers, across different server types and configurations.

Master Server

CrossBox Master is installed on a separate machine or VM and creates an abstract around all slave servers behind it. It runs three essential services that make this possible.

MailProxify

Lets you create floating IMAP/SMTP/POP3 hostname(s) that work across the cluster.

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MX One

MX One service exposes floating MX record(s) for all servers within the cluster.

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Webmail Central

A centralized Webmail URL(s) that work for all servers within the cluster.

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MailProxify

With MailProxify, you can abstract dozens of IMAP/SMTP/POP3 hostnames into a single one.

  • The floating hostname works for any device or application, and the cluster is simply seen as a single server, even with dozens of slave servers behind it.

  • The domain gets automatically resolved, and mail traffic routed to the slave server holding the email account.

  • As you scale, you can add or remove servers from your cluster, and the routing gets automatically applied to the floating IMAP/SMTP/POP3 hostname(s).

  • In combination with White-label, your resellers and clients can create their own branded IMAP/SMTP/POP3 floating hostnames.

  • Efficient IMAP/SMTP/POP3 proxy protocols written in Golang can handle 10K connections per 1CPU and 1GB of RAM.

MX One

MX One service provides a single MX record for the entire cluster.

  • It works for any device or application, and the cluster is simply seen as a single mail server, even with dozens of slave servers behind it.

  • Automatically routes mail traffic through the appropriate slave server holding the email account.

  • Easier customer onboarding with Autodiscover/Autoconfig support.

  • Easier migration of users between servers, as there is no need to change the MX record. The domain's mail traffic gets automatically rerouted to the new server.

  • As you scale, you can add or remove servers from your cluster, and the routing gets automatically applied to the floating MX hostname(s).

  • Acts as a backup server at the same time. Queues emails if the destination slave server is unavailable and redelivers emails automatically once the server is up again.

  • In combination with White-label, your resellers and clients can create their own branded floating MX hostnames.

Single Webmail

Makes it possible to have a single Webmail URL that works for the entire cluster.

  • No unnecessary IMAP/SMTP configurations for the users — They only need an email address and a password.

  • Users can recover access to email addresses themselves using multiple recovery options.

  • In combination with White-label, your resellers and clients can create their own branded Webmail hostnames.

  • In combination with the App Connector, cluster integration of popular apps like Roundcube and Nextcloud is also possible.

Additional Benefits

More subtle but none the less great additional benefits of running the CrossBox Cluster.

Clean Email Traffic

The master server keeps track and blocks offenders automatically, so only the clean mail traffic gets forwarded to the slave servers.

Backup MX

If the slave server is offline or unreachable, the master server will queue the slave server's emails and deliver them automatically once the server becomes available again.

Autoconfig and Autodiscover

The master server also exposes Autoconfig and Autodiscover configuration files, so email clients like Outlook and Thunderbird can automatically prepopulate IMAP/SMTP/POP3 values.

Secure Protocols Out of the Box

With Let's Encrypt built-in, SSL certificates are automatically issued end secure ports enabled for all protocols.

Creating a CrossBox Cluster is not as complicated as it sounds. Adding a slave server is easy and can be completed in a couple of minutes from the admin area. Apart from the master server, there is no need for additional infrastructure — You can use any combination or number of your existing cPanel, DirectAdmin, Plesk or Standalone servers as your immediate cluster slaves. Best of all, it doesn't require any modification on the slave servers currently running services. It's a true plug-n-play solution.