The services that run on the front-end nodes of the cluster are only the proxy services. All of these services can run on any number of systems without affecting the overall cluster availability. As long as one of the front-end nodes is still serving incoming requests, the cluster will be fully functional.

Because all front-end nodes are identical, you can add or remove nodes at will. The more front-end nodes your cluster has, the more requests will be processed at the same time. It is important to have sufficient front-ends to keep up with the number of the requests, especially during peak activity times.

The following services provide proxy abilities within AXIGEN:

• SMTP Proxy routes and authenticates incoming SMTP sessions. This service is vital for mail delivery within the cluster.
• IMAP Proxy routes and authenticates IMAP sessions. This service allows users to retrieve their messages from their back-end account through the proxy using the IMAP protocol.
• POP3 Proxy routes and authenticates POP3 sessions. This service allows users to retrieve their messages from their back-end account through the proxy using the POP3 protocol.
• WebMail Proxy routes and authenticates WebMail access requests. This service also renders the web pages requested by the web browser, using the information retrieved from the back-end server holding the user account.

See subsections of current page for more details:

The SMTP Proxy
The IMAP and POP3 Proxies
The WebMail Proxy
Mapping Setup