We've got the following in production...



4 Old Dell GX1 PCs
PII 350 MHz Processors
512 MB RAM
100 MB Internet Lines
4 Legged Firewalls
Always on, always connected

One Firewall is Master and the other three are Backups.
Why four Firewalls?  ...because we could.
The Master's CPU is usually 98% idle.
These PCs can be bought for next to nothing in Akihabara.
We can upgrade Firewalls without incurring any downtime.