What are some alternatives?
When comparing IPFire and ZeroShell, you can also consider the following products
pfSense - pfSense is a free and open source firewall and router that also features unified threat management, load balancing, multi WAN, and more
OPNsense - OPNsense® you next open source firewall. Free Download. High-end Security Made Easy™. Offers Intrusion Prevention, Captive Portal, Traffic Shaping and more.
MikroTik RouterOS - The main product of MikroTik is a Linux-based operating system known as MikroTik RouterOS.
OpenWrt - OpenWrt is an open-source firmware based on Linux for wireless routers
Endian Firewall Community - Endian Firewall Community (EFW) is a "turn-key" linux security distribution that turns...
ClearOS - A very good alternative for Windows Server, for free