General Knoppix support for those who've read the FAQ at the Wiki
Palo Alto PA-3020 Network Security Appliance
$75.00
Fortinet FortiGate-40C Network Security Firewall
$42.50
NetFu Firewall 1U, Intel CPU, 8 x Gigabit, SFP, w/ pfSense, Others, NEW OPTIONS
$541.85
Fortinet Fortiwifi 60D FG-60D Security Appliance Firewall / VPN w/ AC Adapter
$34.97
Palo Alto PA-220 Security Appliance Firewall - NO Power adapter -
$33.00
Ubiquiti Networks UniFi Security Gateway - White (USG-3P)
$49.00
PFSense F80 Firewall | Atom C2358 CPU | 4 Gigabit Ports | 2GB RAM | FANLESS
$75.00
Cisco ASA5506-K9 ASA 5506-X Network Security Firewall
$49.99
Genuine Fortinet FortiGate 60E-POE Firewall Network Security ATP Bundle 2 years
$263.99
Pulse Secure PSA3000 Security Firewall Appliance SSL VPN
$69.99