Yes, there are open source alternatives to Domino Servers and Notes clients that address rich e-mail, calendaring, groupware applications and instant messaging in your organization. There is, however, one very important difference. Domino/Notes is composed of a series of highly integrated applications from a single vendor. A comparable open source solution will include multiple best-of-breed components that are integrated through open standards.
You'll need to assess the capabilities and architecture of a single-vendor solution versus the open source advantages of openness and flexibility. Because Domino servers and multiple commercial and open source alternatives are available on the Linux platform, you can proceed with your Windows-to-Linux migration knowing that you have alternatives.
Here are some applications on Linux that may address the functionality you currently get from Domino/Notes:
- For creating database and groupware applications you can use the popular "LAMP" stack: Linux operating system, Apache middleware, MySQL databases and PHP, Perl and Python tools.
- For Linux e-mail and calendar servers you may want to consider Groupwise, Bynari, Stalker, OpenExchange and Scalix.
- GAIM, Jabber and Kopete are popular Instant messaging choices.
- There are many other Linux offerings that can round out your solutions.
Finally, migrating to a different solution set for e-mail and collaboration doesn't necessarily mean a higher conversion cost than continuing with Notes/Domino. I'd advise you to undergo a closer comparison to determine what the most cost-effective route is.