Part 1 — A PC Built to Guard the Network
Most old PCs eventually reach a point where their original purpose no longer makes much sense.
Gaming performance becomes inadequate. Storage becomes inconvenient. Power consumption starts to look excessive compared with modern hardware.
But sometimes the hardware itself still has something valuable to offer.
In the case of Guardian, that something is connectivity.
The machine is based on an Intel Core 2 Quad Q6600, an ASUS P5W DH Deluxe motherboard and 8 GB of DDR2 memory.
There is no modern gaming GPU in the system.
Instead, almost all of its expansion capability is being devoted to something much less glamorous but, for this project, much more interesting:
the network.
Guardian will run a Linux server operating system and its primary purpose is to provide network-oriented services rather than act as a conventional desktop PC.
But there is one particularly important role for which I have planned it.
Guardian will sit between the cable internet modem and the main home router.
In other words, the internet connection will normally follow this path:
Cable modem → Guardian WAN → Guardian LAN → network switch → main router WAN
This gives Guardian a position at the edge of the home network, where it can act as a gateway and security point.
Why Guardian?
The name came from this role.
I have several older PCs at home that still have useful purposes but run operating systems such as Windows XP and Windows 7.
Those machines are interesting from a historical and hardware perspective, but connecting legacy operating systems directly to the modern internet is obviously a very different proposition from using a current operating system with contemporary security support.
Rather than expecting these old computers to become modern, I wanted to put something modern in front of them.
Guardian can act as a security and network boundary between these legacy machines and the wider internet.
The old PCs can remain part of the network for the jobs where I still need them, while Guardian provides a modern Linux-based network layer in front of them.
That is where the name started to make sense.
It isn’t just a server.
It is there to guard the machines behind it.
From Computing to Connectivity
The original idea behind an enthusiast PC was usually to maximize computing performance.
Guardian takes almost the opposite approach.
The CPU is old.
The memory is old.
The motherboard is old.
But the network interfaces are anything but typical for a Core 2 Quad machine.
The system currently has:
- 1 × 10 GbE Ethernet
- 2 × 2.5 GbE Ethernet
- 2 × Gigabit Ethernet onboard
- 2 × Gigabit Ethernet on PCI cards
- A PCIe-to-NVMe adapter
That gives Guardian seven Ethernet interfaces in total, spanning several generations of network connectivity.
The Q6600 doesn’t need to be particularly fast to make this interesting.
The network is the hardware worth looking at.
Why So Many Ethernet Ports?
Having multiple network interfaces isn’t simply about making the specification look impressive.
Each interface can have a different role.
The 10 GbE connection can provide a high-bandwidth link where speed matters.
The two 2.5 GbE interfaces can serve modern network segments and devices that don’t require a full 10 GbE connection.
The four Gigabit Ethernet interfaces — two onboard and two on PCI cards — provide additional connectivity for older equipment, separate network segments or dedicated links.
This makes Guardian much more than a conventional server with a single Ethernet port.
It becomes a network junction and gateway.
The old motherboard provides the platform, but the network adapters define the machine.
The Main Gateway
The most important job is its position between the cable modem and the main router.
Under normal operation, the modem connects to Guardian’s WAN interface. Guardian handles the traffic before passing it into the rest of the home network.
Guardian’s LAN side then connects to the network infrastructure and ultimately to the WAN port of the main router.
This arrangement gives me a dedicated machine where network-level functions can be implemented independently of the main router.
It also means that Guardian can become a useful place for firewalling, routing, monitoring and other network services without requiring the main router to do everything.
The machine therefore becomes part of the infrastructure rather than simply another computer attached to it.
The Power-Outage Fallback
There is another part of the design that is particularly important because a gateway is only useful when it is actually running.
Guardian will normally be part of the internet path, but I don’t want a power outage to leave the entire home network without internet access simply because an old PC has shut down.
The fallback plan is therefore to use a TP-Link router running OpenWrt as a kind of software-controlled matrix switch.
Under normal conditions, the network path is:
Cable modem → Guardian WAN → Guardian LAN → matrix-switch router LAN → main router WAN
If the electricity goes out, Guardian can shut down while a UPS keeps the cable modem, the fallback router and the main router running.
The OpenWrt router can then change its role and connect the cable modem directly to the WAN side of the main router:
Cable modem → fallback/matrix router → main router WAN
In effect, the OpenWrt router becomes a software-controlled bypass.
Guardian can disappear from the path without requiring someone to physically move Ethernet cables.
This also gives the project an interesting level of redundancy.
The machine guarding the network doesn’t have to be available every second for the network to remain functional.
An NVMe Drive on a Core 2 Quad
The storage follows the same philosophy.
The P5W DH Deluxe obviously predates NVMe.
Rather than accepting that limitation, I added a PCIe-to-NVMe adapter.
It is another example of mixing generations deliberately.
There is something amusing about an old Core 2 Quad platform communicating through a modern NVMe SSD while simultaneously handling 10 GbE and 2.5 GbE networking.
None of these technologies were designed to coexist in a system like this.
But PCIe provides the common language that makes the combination possible.
And that is one of the reasons older enthusiast platforms can still be interesting.
They often provide more expansion capability than their age would suggest.
The Graphics Card That Almost Doesn’t Matter
Guardian does still need a way to provide basic display output during installation and administration, but graphics are deliberately given the lowest priority.
For now, that is handled by an old PCI graphics card rather than a PCIe GPU.
The reason is simple:
PCIe slots are valuable resources in this machine.
With a 10 GbE adapter, two 2.5 GbE adapters, the NVMe adapter and the other expansion possibilities, every PCIe slot can potentially serve a much more useful purpose than graphics.
An old PCI graphics card is therefore perfectly adequate for basic setup and administration.
But I also want to try something even more appropriate to the idea behind Guardian: booting the motherboard without a graphics card at all.
If the P5W DH Deluxe can initialize and boot successfully without a GPU, there is little reason to keep even the old PCI graphics card installed.
The machine could then dedicate its expansion resources almost entirely to networking and storage.
That would make the philosophy of the system even clearer:
Guardian doesn’t need a graphics card. It needs network ports.
Why Linux?
The choice of a Linux server operating system follows naturally from the intended role of the machine.
Guardian isn’t going to be used as a conventional desktop. There is no need for a graphical desktop environment consuming resources simply to provide an interface that the machine doesn’t really need.
A Linux server installation allows the system to operate primarily through the network and provide the services for which it is intended.
It also gives me a modern and actively maintained software environment around hardware that is almost two decades old.
That is particularly important when Guardian is going to sit at the edge of the network.
The old hardware may be obsolete, but the software providing the security and network functions doesn’t have to be.
An Enthusiast Motherboard Finds a New Purpose
The ASUS P5W DH Deluxe is also an interesting foundation for the project.
It comes from a period when enthusiast motherboards were designed with considerably more expansion and connectivity than many ordinary users actually needed.
That makes it almost the opposite of a modern minimalist motherboard.
Instead of treating its age as a disadvantage, Guardian can take advantage of that expansion-oriented design.
The motherboard doesn’t need to be fast by modern standards if it provides enough of the interfaces and expansion possibilities needed for the job.
This is one of the reasons I find older enthusiast platforms particularly interesting.
Their useful life doesn’t necessarily end when they become too slow for their original purpose.
Sometimes the platform itself becomes more interesting once you stop using it for what it was designed to do.
The Network Is the Computer
There is an obvious temptation when working with old hardware to measure everything against modern hardware.
How much slower is the Q6600?
How much power does it consume?
How much faster would a modern mini PC be?
Those are reasonable questions, but they aren’t necessarily the most interesting ones.
A modern low-power PC would almost certainly be faster, smaller and more efficient.
But if the objective were simply to build the best network server possible, I wouldn’t be starting with a Core 2 Quad.
The objective is different.
I want to find out whether an old enthusiast platform can become useful again by giving it a completely different job.
Guardian is therefore not an attempt to make the Q6600 behave like a modern processor.
It is an experiment in making an old platform useful through connectivity rather than computing performance.
The newer PCs can concentrate on gaming, engineering, media processing and other demanding workloads.
Guardian can concentrate on the less glamorous but equally important infrastructure underneath them.
It can connect machines, protect legacy systems, provide services and act as a central point between different parts of the network.
And this is perhaps the most interesting form of hardware revival.
Instead of trying to make an old PC perform like a new PC, change what you expect from it.
The Q6600 doesn’t need to compete with a modern processor.
The P5W DH Deluxe doesn’t need to compete with a modern motherboard.
They simply need to provide a reliable foundation for a machine whose most important components are the ones carrying packets rather than rendering pixels.
Guardian isn’t an old PC pretending to be new.
It is an old PC doing something new.
Continue with Part 2