There are endless free and open source software solutions and services out there for use in the network—for small, medium, and enterprise environments. You aren’t limited to Microsoft, Cisco, and other commercial giants. You can save money by using free, open source, or less expensive solutions. Here I’ll share a couple you might consider.
Vyatta Enterprise-level Firewall/Router
Vyatta is a network operating system targeted for enterprise-level networks for cloud, virtual, and physical deployments. It offers the core network services: NAT, routing, DHCP, firewall, VPN, QoS, IPS, and more. It can install onto any standard x86 based system, run using VMware, Citrix XenServer, Xen and Redhat KVM hypervisor environments, or on Amazon VPC. They provide their core open source software for free with documentation, but isn’t recommended for critical networks. The paid subscriptions offer additional features, updates, add-ons, and support.
Endian Enterprise-level Firewall/Router
Endian is a Unified Threat Management (UTM) operating system, enabling you to turn any PC or server into a full-featured security appliance. In addition to providing the basic LAN services (NAT, Firewall, DHCP, etc.), it also offers VPN, hotspot functionality, anti-virus, anti-spam, web security, and email content filtering. Like Vyatta, their free open source community version of the OS isn’t designed for critical networks.
RouterOS Enterprise-level Firewall/Router
RouterOS is a closed source Linux-based operating system (OS) designed to implement a router. It’s the same OS offered on the Router BOARD hardware from MikroTik. However, the OS is freely downloadable and installable onto regular PCs and servers, turning it into an enterprise-level router. It offers all the network services for a LAN, including routing, firewall, bandwidth management, wireless access point, backhaul link, hotspot gateway, VPN server, and more. However, only basic functionality and limited use of some features is free. After the 24-hour fully functional trial, you can purchase a license starting at $45.
Untangle SMB-level Firewall/Router
Untangle is another network operating system, but is targeted more for small-to-medium sized businesses. It can be installed and ran on a normal dedicated PC. It can provide the router (with NAT, firewall, DHCP, etc.) for your network and/or provide additional security and control, such as web and spam filtering, virus and spyware protection, captive portal, a VPN server. The paid premium services then offer enhancements to these features and additional user and bandwidth management functionality.
389 Directory Server
The 389 Directory Server, previously known as the Fedora Directory Server, is a free and open Linux-based enterprise-class LDAP server. It can be an alternative solution to or compliment Microsoft’s Active Directory. It supports install on Linux, Solaris, and HP/UX 11 systems. It’s highly reliable and scalable with multi-master replication. It features a graphical console for managing the server, users, and groups.
Citadel for Email, Calendar, and Collaboration
Citadel is a Linux-based open source groupware solution to manage and offer email, calendar, contact management, and other collaboration features to your users. It’s available as a Debian/Ubuntu package, or downloaded as a VMware appliance. Users can access the services via a web-based interface or via supported clients, such as Outlook, Mozilla Thunderbird and Sunbird, Evolution, and KOrganizer.
SOGo for Email, Calendar, and Collaboration
SOGo is another Linux-based open source groupware solution, offering email, calendar, and contact management to your users. Binary packages are available for several Linux distributions and it’s available as virtual appliances. Unlike most other open source Groupware solutions, the connectors for Outlook and Thunderbird are available for free. Additionally, it also supports all the major mobile smartphones and devices, either natively or via a free SOGo connector.
OpenDNS for Fast and Intelligent DNS and Content Filtering
OpenDNS is a third-party DNS service you can use instead of your ISP’s. It’s a fast and intelligent DNS service that can protect against DNS-based attacks and malware/botnet activity. Additionally, it can provide DNS-based content filtering to automatically block phishing, malware-infested, proxy, adult, and other dangerous sites. You can also view usage reports on Internet activity. It even features the ability to create shortcuts, or words you can type into a browser that will automatically point to a website or IP address.
FreeNAS for a Network File Server
FreeNAS is one of the most popular open source network-attached storage (NAS) software solutions. It installs onto systems with a Compact Flash, USB flash, hard drive, or booted directly from a LiveCD. It offers sharing attached drives via following native protocols: SMB/CIFS (Windows), AFP (Apple/Mac), and NFS (Unix/Linux). Additional supported protocols include FTP, TFTP, RSYNC, Unison, iSCSI and UPnP.
It supports advanced networking with VLAN tagging, link aggregation, and Wake on Lan (WoL). The monitoring features include S.M.A.R.T (smartmontools), email alerts, SNMP, Syslog, and UPS support. You’ll also find extra services: bittorent client (Transmission), UPnP server (FUPPES), iTunes/DAAP server (Firefly), webserver (lighttpd), and network bandwidth measure (Iperf).
Nagios for Network Monitoring
Nagios is a monitoring and alerting system to keep tabs on your servers, switches, applications, and services. It features a web-based interface, email and SMS alerts, escalation capabilities, and event handlers to automatically restart failed services. Reports can provide records of alerts, notifications, outages, and alert responses. The solution is also highly customizable and extendable via add-ons, APIs, or code modifications. You can use free open source version for solid monitoring, but they offer a separate version for enterprise-class environments.
DD-WRT Wi-Fi Router Firmware Replacement
DD-WRT is one of the most popular, feature-rich, and well-maintained open source firmware replacements for consumer-level wireless routers, and can also run on embedded systems and PCs. It provides the typical wireless router features in to addition to some advanced or enterprise-level features, including VLAN support, multiple or virtual SSIDs, hotspot functions, and a VPN client and server. It also offers great customization, such as with the startup and firewall scripts. The wireless access point can also serve as a Client, Bridge, or Repeater.
CoovaAP Wi-Fi Router Firmware Replacement for Hotspot Solutions
CoovaAP is an OpenWRT-based firmware replacement for wireless routers, specifically designed to implement a Wi-Fi hotspot. It includes the CoovaChilli access controller, an embedded captive portal, and features bandwidth traffic shaping. It supports a variety of hotspot schemes, including free access with Terms of Service agreement, commercial or paid access, and even WPA Enterprise security with RADIUS accounting.