ClearOS is a simple, open, and affordable operating system with an intuitive graphical web-based user interface and an application marketplace with over 100 apps to choose from, with more being added every day. Leveraging open source software, you decide what applications you need and only pay for the applications and support you want.

ClearOS (also known as the ClearOS System, formerly ClarkConnect) is an operating system based on CentOS and Red Hat Enterprise Linux, designed for use in small and medium enterprises as a network gateway and network server with a web-based administration interface. It is positioned as an alternative to Windows Small Business Server.

Features:
- Stateful firewall (iptables), networking and security
- Intrusion detection and prevention system (SNORT)
- Virtual private networking (IPSEC, PPTP, OpenVPN)
- Web proxy, with content filtering and antivirus (Squid, DansGuardian)
- E-mail services (Webmail, Postfix, SMTP, POP3/s, IMAP/s)
- Groupware (Kolab)
- Database and web server (easy to deploy LAMP stack)
- File and print services (Samba and CUPS)
- Flexshares (unified multi-protocol storage which currently employs SMB, HTTP/S, FTP/S, and SMTP)
- MultiWAN (Internet fault tolerant design)
- Built-in reports for system statistics and services (MRTG and others)