This really takes me back. My first actual 'use' for Linux was making routers out of leftover computers.

The perfect machine back then was a 100MHz Pentium, in a slimline desktop case. At the time, the Pentium III was the current desktop chip, so you'd have a pile of early Pentium-class machines to use. And even a 10mb ISA network card (3Com if possible) would have plenty of power for the internet connections of the day. But 100mb PCI cards were still fairly cheap.

Install two NICs, load your favorite Linux distro, and then follow the IP-Masquerading HOWTO and you've got internet access for the whole apartment building, office, or LAN party.

Eventually I moved on to Linux Firewalls by Robert Ziegler for a base to build on.

After that I started piling other services on, like a spam filter, Squid cache, it was amazing to get so much use out of hardware that was going to just get thrown out.

Squid caching takes me back. I was dealing with a network for a large car dealership (2006), and they were having issues with pages appearing out of date, as well as sales people who couldn't help themselves from looking at adult websites. I had to figure out the entire network (was put in place before I ever showed up to provide support), which included both the physical and software layers. Not only was I on ladders in the service area, using a network tone device (for those that don't know, you can connect a cable to a device that pushes a tone down the line, and then pick up that tone on a device that lets you run the device down the line and hear the one if you have the correct wire), but I also had to figure out this server using a Squid cache that stood in front of everything.

Eventually I got all the devices marked from origin to their patch cables in the server room, and I started looking into the Squid cache. It turns out that they were caching everything, as well as blocking websites. I figured out what websites they needed to do their job, and turned off caching, while also learning the ACLs for blocking websites. Anything else was allowed, but the Squid cache would hold a copy for some set amount of time (I think it was 24 hours, so if it was legitimate they only had to wait a day, but it also saved on bandwidth by quite a bit - although think this was used more to monitor user activity).

It was frustrating as someone new to large LANs, as well as to in-house caching, but had been using Linux since an early version of Slackware in the later 1990's. Even to this day, as someone that writes software and does DevOps, that knowledge has helped my debugging skills tremendously. Dealing with caching is a skill I feel you need to be burned by in order to finally understand it, and recognize when it's occurring. I cut my teeth on Linux through a teacher that set up a web server in 1997, and not only gave students access to upload their web files, but also a terminal to message each other and see who was online.

That takes me back, I had the same trajectory , getting a newspaper’s news room and offices online with a single computer sharing its ISDN connection. Think ours was also a 100mhz gateway 2000 computer or some such.

That snowballed into “we want a website do you know how to do that?” and. Well, no, but it had Apache available and I … figured things out enough to take the skills elsewhere.

Repeated the same trick with a place in Wisconsin, who initially shared a 56k dialup connection with all their dispatchers and were impressed the thing had stayed up for 900 days without even redialing. 90% of their work was done in an on-prem wyse terminal anyway, dialup used to do the job for email or googling an address.

27, 28 years later I’m still dragged in front of them once in a while to ask how they can accomplish something cheaply with Linux, bubble gum, paper clips, or whatever . The times and technology have changed, but not how cheap they are!

I briefly put a Pentium MMX 200MHz system in service a few years back to bridge my parents to their neighbor's WiFi (with consent of course) when their DSL line was down for a few days. I installed a PCI Ethernet and WiFi card, booted into OpenBSD, and amazingly it was fast enough to get them through the downtime. :)

Someone need to write a new book on Linux router.

The old one is getting really old now, nearly 25 years ago [2].

[1] Book Review: Linux Routers - A Primer for Network Administrators, 2nd Ed:

https://www.linuxjournal.com/article/6314

Inverted case here, my first real use cases for Linux was flashing routers with openwrt and doing fun stuff!

Hell, you could do this with a single NIC if you have a VLAN-aware switch.

Ha, that's very close to my story as well. I had a 166Mhz Pentium and it was all PCI cards and 100mbit by then. That was essentially the start of my career.

You guys with your dedicated hardware. :)

I did routing duties for my LAN with my primary desktop for about a decade, variously with Linux, OS/2 (anyone remember InJoy?), and FreeBSD -- starting with 486 hardware. Most of that decade was with dial-up.

The first iteration involved keying in ipfwadm commands from, IIRC, Matt Welsh's very fine Running Linux book.

WAN speeds were low; doing routing with my desktop box wasn't a burden for it at all. And household LANs weren't stuffed full of always-on connected devices as they are today; if the Internet dipped out for a few minutes for a reboot, that wasn't a big deal at all.

I stayed away from dedicated hardware until two things happened: I started getting more devices on the LAN, and I saw that Linksys WRT54G boxes were getting properly, maturely hackable.

So around 2004 I bought a WRT54GS (for the extra RAM and flash) and immediately put OpenWRT on it. This lead to a long rabbit hole of hacks (just find some GPIO lines and an edge connector for a floppy drive, and zang! ye olde Linksys box now has an SD card slot for some crazy-expensive local storage!).

I goofed around with different consumer router-boxes and custom firmware for a long number of years, and it all worked great. Bufferbloat was a solved problem in my world before the term entered the vernacular.

And I was happy with that kind of thing at home, with old Linksys or Asus boxes doing routing+wifi or sometimes acting as extra access points... until the grade of cheap routers I was playing with started getting relatively slower (because my internet was getting relatively faster) and newer ones were becoming less-hackable (thanks, binary blob wifi drivers).

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I decided to solve that problem early in 2020. Part of the roadmap involved divorcing the routing from the wifi completely -- to treat the steering of packets and the wireless transmission of data as two completely distinct problems.

I used a cheap Raspberry Pi 4 kit to get this done. The Pi4 just does router/DNS/NTP/etc duties like it's 1996 again. Dedicated access points (currently inexpensive Mikrotik devices) handle all wifi duties.

That still works very well. Pi4 is fast enough for me with the WAN connections available here (which top out at 400Mbps) even while using SQM CAKE for managing buffers, and power consumption of the whole kit is too low to care about.

The whole OpenWRT stack just plods along using right around 64MB of RAM. VLANs are used to multiply the Ethernet interface into more physical ports (VLANs were used to do this inside the OG WRT54G, too).

It's sleepy, reliable, and performant.

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And it'll keep being fine until I get a substantially-faster WAN connection. For that, maybe one of the China-sourced N150 boxes, with 10gb SFP+ ports, will be appropriate -- after all, OpenWRT runs on almost anything including AMD64 and the UI is friendly-enough.

But there's no need to upgrade the router hardware until that time. Right now, all of my routing problems are still completely solved.

> The perfect machine back then was a 100MHz Pentium, in a slimline desktop case. At the time, the Pentium III was the current desktop chip, so you'd have a pile of early Pentium-class machines to use. And even a 10mb ISA network card (3Com if possible) would have plenty of power for the internet connections of the day.

I was doing the same. Router and firewall on old Pentium CPUs. I don't have these machines anymore but I still have HDDs from back then with post-it notes on them saying stuff like: "Linux firewall / HDD 120 GB". For whatever reason my HDDs adapter that can read just about everything doesn't have the correct pin out for those HDDs. Would be a blast if they were to still boot: at some point I'll just buy a compatible adapter and see what I can find on those HDDs. I was very likely also saving some backups there.

But really my best memory was years (I think) before 120 GB HDDs became an affordable thing, in the super early Slackware days, on a dial-up connection: I had a 486 desktop computer and I'd share the Internet connection to a very old laptop (!) using... PLIP. A printer cable and the Parallel Line Internet Protocol. Amazing hack: my brother and I could then both use Netscape at the same time and to us this felt like a glimpse into the future.