DROP

Nerd rage.

Fixed a recent problem in which I set up the conditions for failure years ago.

My Linux PC at home has been having hardware issues. It’s been in service for 13-ish years and, electronically, it’s falling apart. It was kernel panicking while transferring files from my phone over USB3. After enough of this, I set about to diagnose and debug why it was panicking.

During this action (wherein I hulk-smashed some memory sticks and permanently damaged 2 of the 4 DIMM slots, like an asshole), other problems cropped up. For instance, NetworkManager appeared to have lost the network config, so I set it back up. “Oof, there might be file corruption! I need to find a new PC.” Also found some pictures that I had copied that were also corrupted (thankfully I had backups in a zip file). Huh! That’s concerning, because I also have a mail server on this machine.

So, I noticed later that I was unable to reach that mail server from my phone when I was out on my 4G connection. Using Wireshark, I found the TCP SYN packet was getting through the gateway and landing at the PC, but the PC wasn’t sending back a SYNACK. It was just dropping. Likewise, I couldn’t ssh into the machine from outside. Those packets were also being dropped.

I won’t go into the details of all the hacks and fixes and searches I tried for finding out WTF was happening. There were many hacks. Oh, so many. I should know this! Because I’m an expert at computering, I’ll have you know. Expert!

Dreamed about it this morning, how I’d look at iptables and examine all the rules and try that angle. So I got up and bashed my forehead against the screen. Dumped the rules and pored over them all. It should work! But it didn’t.

Years ago, when reinstalling this PC after a crashed disk, I set the iptables INPUT chain to have the default rule DROP, so it would ignore all inbound traffic that’s not approved (don’t worry, the local LAN is in the whitelist). So, on a whim, I changed the default rule to ACCEPT. And you know what happened?

I could reach my mailserver.

So one of the rules is fucking me over.

:INPUT DROP [31:9840]
-A INPUT -i lo -j ACCEPT
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -i enp3s0 -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT
-A INPUT -i enp3s0 -p tcp -m state --state NEW -m tcp -m multiport --dports 25,143,993 -j ACCEPT
-A INPUT -i enp3s0 -p tcp -m state --state NEW -m tcp -m multiport --dports 80,443 -j ACCEPT

On their face, these rules are perfect and acceptable and should work.

But wait! What’s this?

root:/# ip a
2: enp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000

Where the fuck did enp3s0 get off to? Ah goddammit. When the USB3 chipset disappeared along with its Southbridge root controller, the Linux kernel enumerated the Ethernet interface at a different name. enp3s0 became enp2s0, and suddenly my firewall rules no longer matched. Packets dropped.

NERD RAGE.

I’m a dullard and a fool. I shot myself in the foot, but only after going for the long play. Why did I bind the rule to the interface name? Why not wildcard? I’m an idiot.

I removed the -i interface matches from the iptables rules so they bind to the wildcard interface, and set the INPUT chain default rule back to DROP, and everything works again.

Really, this highlights the importance of getting off of this failing hardware before true corruption happens. Toward that goal, I bought a gaming PC from a friend (actually built in this decade), and I need to migrate to it this week while I design and purchase a new PC in the coming month now that xmas is over.

Dammit, y’all. God dammit.

Teatime of the Sophisticate

Was a moment in college when I had friends who were reaching for sophistication, and I had it in my mind that I could be sophisticated too. Tea was a popular thing at the cafeteria table. So I went out and bought an electric tea kettle and a box of tea bags, just in case one of them wanted to hang out in my dorm lobby with me while we drank tea.

(Seriously, I have no idea where these ideas come from, other than brute naivete.)

Thing is, I never actually made tea in my own room. I never brewed a cup, never guessed at why we drink tea. I never learned how to do it right, how to make good tea, using up tea bags in the pursuit of excellence and sophistry. I didn’t want to waste rare money and use up supply in order to get better. I wanted it to be on the ready just in case. So it just sat in a box, waiting. Waiting for me to call someone over for tea. Tea that most certainly would have been less than passable.

But I never called anyone.

That bundle of facts still fucks me up.

We get better by using our tools in the pursuit of excellence. We learn nuance, choices, options, tweaks, effects. We come to understand the properties of our medium. Therein is the sophistication. It’s not the act of presenting and providing; it’s the process of learning preferences.

I was a bobblehead. I am a bobblehead still, and will continue to be a bobblehead. My sophistication comes now in the form of knowing my nature by divining what had been in front of me the whole time while I was trying too hard.

Introspection. Retrospection. Perfection.

At this age, I’ll take what I can get.

Seattle Travelog, Observations

Part of a series from the travelog of my trip to Seattle in October 2022. This is a reflection written a few days after the trip.

A cool thing about Seattle is how they treat pedestrians. Just like Portland, drivers will slam their brakes and wait patiently for people to walk across. That’s not to say you should blaze across every intersection; even on the non-signalized intersections, it’s smart to look before crossing. I assume that drivers are also pedestrians when they’re not behind the wheel. So they know. That’s nice.

Not so many bikes, oddly. Too many hills and mountains. More electric scooters. I’d need one if I lived there. More people owning their own electric kick scooters. Nice. Even the rental Lime scooters are beefier than ours — bigger motors, removable battery packs. Smart. These are geofenced though, so you can’t ride them through parks. Found that out.

But walking without fear from drivers is nice. Super nice. Austin proves we are still in Texas. The driver culture here blames pedestrians for not walking correctly. It only takes the stroke of a legislator’s pen to fix this.

Until then, I long for the safety of the Pacific Northwest.

Despite being a bigger city than Austin, and significantly more diverse, from what I saw, the people are just as tired, but more hopeful, and definitely more willing to keep to themselves when out in public. I walked past heated arguments, shady deals, sketchy people just chillin’, people crying, lovers swooning, whatever, and the spirit there is, “eh, that’s not my problem.” And, to be honest, I kinda like that.

I came from small towns where anybody at any time could be the target of fuckwith for absolutely no reason other than just existing. Happened to me plenty. Big cities, everybody’s too busy getting there to bother. There’s a yarn about NYC being the city where you can go walk down a crowded street just to be alone. That’s a big-city adaptation, or else people will go insane.

People in Seattle are diverse, scattered, collected into buses, jostled together, and at the end of the day, they’re just trying to get to where they’re going. Once they get there, they’re chatty, friendly, and interesting. It’s a hard-soft balance.

He is no man who returns from a journey unchanged. I’m still overwhelmed. Still silent. Still processing. This is a good break from my habits. I need them to stay broken. Open up to other places to be, other modes, other thoughts. After a week of this fresh air, I need more freshness.

Fuckin’ Seattle.

Worth the experience.