All companies must secure their networks with strong security systems, and small and medium-sized enterprises are no exception. But security is not incompatible with cost savings. Currently there are Open Source firewall which can suit SMBs' needs:
-Endian Firewall. This software is a Linux distro optimized for security works. It provides firewall, intrusion prevention and detection, anti-virus, anti-spam, VPN and secure remote access, and high availability. There's a free edition and a commercial version with advanced features and add-ons support.
-IPCop. It is a free software to be installed on your existing hardware which includes packet filtering, proxy, traffic shaping, VPN and secure remote access, user authentication, name services and time server. In addition, it provides performace graphics and system monitoring to make it easy to identify any issue. It is completely free and offers community support only.
-OpenWRT. It is an access point with ethernet ports, wifi, and management software. Updating the firmware you can use it as firewall and router for small networks, as secure wireless access points, or to set up wireless hotspots. It is free os costs and no support is available.
-PfSense. This company offers a wide range of networking products, including a free community edition, hardware appliances, and cloud services. SG-2440 PfSense Security Gateway Appliance may be a good choice, since it provides secure VPN to give remote workers access to your network, policy routing, advanced routing, captive portal...
-Untangle Gateway. It manages user authentication VPN, captive portal, web filtering, anti-virus, anti-spam, intrusion prevention, ad blocker, reporting, and higher-end features such as WAN balancing and automatic failover. The basic edition is free and you can purchase different add-ons.
For more information on these systems, read the full article