Badabinski

PART 3.
They made their STUPID MODEMS FUCK WITH THE FTP PACKETS. I have personally experienced this with Comcast Business. The stupid piece of shit DOCSIS modem they provide intercepts the FTP packet from your server saying "oh, connect to this address: x.x.x.x:44010" and they rewrite the fucking address to the public IP. There is no way to turn just this horse piss off. Now, for average business customers, this probably saved Comcast a bunch of money in support calls. However, if you're using the so-called bridge mode on that degenerate piece of shit-wrapped-silicon (where rather than allowing the modem to give you a DHCP address, you just configure your system to have one of the addresses in the /29 space and the modem detects that and says oh okay don't NAT traffic when it's going to this address, just rewrite the MAC and shunt it over the right interface), then something funny happens. The modem still rewrites the contents of the packet, but it uses the wrong fucking IP address! Because the public IP that your server is running on is no longer available to the modem, the modem just chooses another fucking address. Then, the client tries to connect to 1.2.3.5 instead of 1.2.3.4 where your server is listening, the modem says "hey I'm 1.2.3.5 and you can fuck off, I'm dropping your SYN for port 44010", and I get an angry call from the client asking why they can't download their files using this worthless protocol. I remember having a conversation like this:

Me: "Just use SFTP on port 22!"
Client: "No! FTP is faster/more secure/good enough for my grandfather good enough for me/corporate won't allow port 22."
Me: "Comcast is fucking me right now. What if we lied and served SFTP over port 21?"
# we try it
Client: "It's not working! I can't even connect!"

I couldn't connect either. I couldn't connect to anything. Trying to do SFTP over port 21 caused the stupid fucking modem to CRASH.

Are you starting to see what the problem is? It's like Microsoft preserving bugs in Windows APIs so that shitty software doesn't break, and then they end up doing crazy gymnastics to accomodate old shit like the Windows 8 -> Windows 10 thing where they couldn't use "Windows 9" because that would confuse software into thinking it was running "Windows 95" or "Windows 98". FTP has some bugfuck crazy design decisions that we've collectively decided to just "work around," and it leads to fucking gymnastics.

Speaking of bugfuck crazy design decisions, FTP's default file transfer mode intentionally mangles data!

Continued in part 4.

PART 2.

NAT, much like the city of Phoenix, is a monument to man's arrogance. Fuck NAT and fuck FTP. If your FTP server is listening directly on a public IP address hooked up directly to a proper router, then none of this applies. If you're anything like me, the last company I worked for (a small startup), or my current company (many many thousands of employees making software you know and may or may not hate, making many billions of dollars a year), then the majority of your servers are living in RFC1918 space. Traffic from the internet is making it to them via NAT (or NAT with extra steps, i.e. L4 load balancers).

A request comes in for $PUBLIC_IP TCP port 21 and is forwarded to your failure of a boxen at 10.0.54.187. Your FTP server is a big stupid idiot and doesn't know this. It thinks that it's king shit and has its own public IP address. Therefore, when it's deciding what ADDR:PORT it's going to tell the stupid FTP client to connect to, it just looks at one of the adapters on the box and says "oh, I'll tell this client on the internet to connect to 10.0.54.187:44007" and then I fucking cry. The FTP client is an idiot, but the IP stack on the client's home/business router is not and says "oh, that's an address living in RFC1918 space, I shouldn't send that out over the internet" and they don't get the results of their LIST.

So, how do you fix this? Well, you fix it by not using FTP. Use SFTP USE SFTP USE SFTP FOR GOD'S SAKE. But since this world is a shit fucking place, you have two options. The best option is to configure your FTP server to lie about its IP address. Rather than being honest about what a fool it is, you can tell it to send your public IP address to the client rather than the network adapter IP address. Does your public IP address change? Fuck you, you get to write a daemon that checks for that shit, rewrites your FTP server config, and HUPs the bastard (or SIGTERMs it if your server sucks and can't do a live config reload).

Let's say that you don't want to do that. Let's say you work at a small company with a small business internet plan that gives you static IPs but a shitty modem. Let's say that you don't know what FTP is or how it works and your boss told you to get it set up ASAP and it's not working (because the client over in Bendoverville Arkansas is being told to connect to a 10.x.x.x address) and it surely must be your ISP's fault. So you call up Comcast Business/AT&T/Verizon/Whoeverthefuck and you complain at their technicians for hours and hours, and eventually you get connected to a human that knows what the problem is and tells you how to configure your stupid FTP server to lie like a little sinner. The big telco megacorps don't like that. They don't want to waste all those hours, and they don't want to hire too many people who can figure that shit out because it's expensive. You wanna know what those fucking asshole companies did?

Continued in part 3.

I'd like to interject for a moment. What you're referring to as FTP is, in fact, smelly hot garbage.

For context, I wrote this while waiting for a migraine to pass. I was angry at my brain for ruining my morning, and I like to shit on FTP. It's fun to be hyperbolic. I don't intend for this to be an attack on you, I was just bored and decided to write this ridiculous rant to pass the time.

I must once again rant about FTP. I've no idea if you're serious about liking it or you're just taking the piss, but seeing those three letters surrounded by whitespace reminds me of all the bad things in the world.

FTP is, as I've said, smelly hot garbage, and the infrastructure built to support FTP is even worse. Why? Well, one reason is that FTP has the most idiotic networking model conceivable. To see how crazy it is, let's compare to a more sane protocol, like HTTP (for simplicity's sake, I'll do HTTP/1.1). First, you get the underlying transport protocol stuff and probably SSL. The HTTP client opens a connection from some local ephemeral port to the destination server on port 80/443/whatever and does all the normal protocol things (so syn->synack->ack and Client Hello -> Server Hello+server cert -> client kex+change cipher -> change cipher -> encrypted data). FTP does TCP too! Same same so far (minus SSL, unless you're using FTPS). Next, the HTTP client goes like this:

GET /index.html HTTP/1.1
Host: www.whatever.the.fuck
# a bunch of other headers

and you know what fucking happens here? The fucking server responds with the data and a response code on the same goddamn TCP connection. You get a big, glorious response over the nice connection you established:

200 OK
# a bunch of headers and shit

HERE'S YOUR DAMN DATA NERD

So that's nice, and the client you're using to read this used that flow (or an evolution of that flow if you're using HTTP/2 or HTTP/3). So what does FTP do? It does one of two really stupid things depending on whether you're using active or passive mode. Active mode is the default for the protocol (although not the default for most clients), so let's analyze that! First, your FTP client initiates a TCP connection to your server on port 21 (by default), and then the server just sends this:

<--- 220 Rebex FTP Server ready.

ok, that kinda came out of nowhere. You're probably using a modern client that saves you from all of the godawful footguns, so it then asks the server what it supports:

---> FEAT
<--- 211-Supported extensions:
<---  AUTH TLS;SSL;
<---  CDUP
<---  CLNT
# A whole bunch of other 4 letter acronyms. If I was writing an FTP server, I'd make it swear at the user since there are a lot of fun 4 letter words

There's some other bullshit we don't care about right now, although highlights include sending the username and password in plain text. There's also ASCII vs binary mode. WE'LL GET BACK TO THAT. :|

So then we want to do a LIST. You know what happens in active mode? Your computer opens up some random fucking TCP port. It then instructs the FTP server to CONNECT TO YOUR GODDAMN COMPUTER. Your computer is the server, and the other side is now the client. I would post a more detailed overview of the FTP commands, but most servers on the internet disable active mode because it's a goddamn liability. All of the sudden, your computer has to be internet facing with open firewall ports, and that's just a whole heap of shit.

I'm probably not blowing many minds right now because people know about this shit. I just want to mention that this is how FTP was built. The data plane and control plane are separate, and back in 19XX when this shit was invented, you could trust your fellows on ARPANET and NAT didn't exist and sure HAM radio operators here's the entire goddamn 44.0.0.0/8 block for you to do packet switched radio. A simple protocol for simple times, back before we knew what was good and what was bad.

So, active mode sucks! PASV is the future, and is the default on basically all modern clients and servers! Passive mode works exactly the same as the above, except when the client goes to LIST, the server opens some random TCP port (I've often seen something like 44000-44010) and tells the client, "hey you, connect to 1.2.3.4:44000 to get you your tasty data." Sounds great, right? Well, there's a problem that I actually touched on in my last paragraph. Back when this dogshit was first squeezed out in the 70s, everyone had a public address. There were SO MANY addresses! 4 billion addresses? We'll never use all of those! That is clearly not the case anymore. We don't have enough addresses, and now we have this wonderful thing called NAT.

Continued in part 2.

For Linux applications that respect XDG? Sure. There are plenty that don't because they either predate that specification, or they just don't care. Linux filesystems are generally much faster at executing reads on many small files, meaning fast search tools like ripgrep and fd make it so I don't really have to care. They'll run through my whole $HOME in 5 seconds flat. There's also stuff like locate, although I don't like maintaining an index. SSDs are so damn fast that I can just rg --hidden --glob '*.toml' 'the_setting_i_want_to_change' ~/ whenever I want.

Huh, interesting! Sounds like it'll be perfect for OP.

There's always Termux and whatever you can install there. That sounds silly, but when I download from my phone, I do it using aria2c in Termux. It works great, and everything (AFAIK) is FOSS. zsh + fzf history completion/file finding (<c-T> is a godsend) makes it possible to use a CLI on a phone without going crazy. Only really works well if you're already comfortable with the command line, which is definitely a big if. It works really well for me, but I'm one of those weirdos that doesn't have a graphical file manager installed on their computers.

Eating this stuff would be about as bad as eating any regular cat litter that uses Fuller's earth as the primary absorbent. The extra special ingredient (powdered quartz) is effectively nontoxic when ingested. The real issue is the chronic exposure to very fine silica dust.

Edit: to clarify, I do not believe that it would be safe for humans or animals to use this as cat litter. Just realized that this comment might have been taken as a "well akshually it's fine." It is not fine, silicosis is a dreadful condition.

So I'd like to chime in. It looks the the two primary ingredients for ZEP-o-zorb are Fuller's earth and powdered quartz.

First, Fuller's earth. This is good stuff! It's actually often used as an industrial absorbent for chemical spills (the purpose of ZEP-o-zorb), as well as in some types of cat litter. It totally makes sense why this stuff would work well for you, and I understand why you've been using it for a year. It's perfect for the task and has basically no downsides.

Now, about the powdered quartz... Chemically known as silicon dioxide. It's often refered to as silica. Silica is also good stuff! It's in concrete, it's the main component of glass, and of particular interest for your application, it's very good at absorbing volatile organic smelly stuff. Seems perfect, right?

Unfortunately, powdered quartz has a downside. When it's in a very fine powder, it produces a lot of dust. This silicon dioxide dust is incredibly harmful to your lungs. Long-term exposure to silicon dioxide dust results in silicosis, which is a really serious illness that kills tens of thousands of people every year. Inhaling that dust can also give you lung cancer, lupus, rheumatoid arthritis, or other autoimmune disorders.

I totally understand why you felt that this product was a great option! I don't doubt that it serves as an absolutely excellent cat litter. I had two kitties that took the smelliest shits, and I was always searching for ways to fix that (either through diet, litter, stress reduction, or other things). I also understand how upsetting it can be to share something with people and be met with disbelief, denial, and accusations. However, I really want to urge you to look past all of that and reconsider your use of this product. The silica dust is practically invisible and tasteless, and it had the chance to cause you many years of problems. You and your cat deserve to be healthy.

I'm really glad to hear that you're alright. Several skin conditions are effectively autoimmune disorders, so I'm absolutely not surprised that the treatment is rough—anything that affects your immune system is probably going to make you feel like shit. I have no idea if that's the case, but it seems likely. I hope that your procedure goes well, your treatment is effective, and your condition ceases to be a problem for you. Health and wellness always come first.

This is excellent news! I've been installing from GitHub for a while and have been really pleased with how fluid the app is.

You joke, but using air dropped bombs to put out fires is a tactic that's been used for quite a while. probably not the best thing to do next to a site with nuclear materials on-hand, but it's absolutely been done before.

Game devs specialize in writing code that gets displayed on a GUI. They also have to learn how to do scripting and some decision tree stuff for AI, but from day 1, they're writing for a GUI. Plus, game engines contain a tremendous amount of code that makes it very fast to make GUI. That game engine is huge and complicated and you have to spend a bunch of timing learning how the hell it all works. Software devs outside of the games industry haven't done that, and it would increase the size of a small and simple script from 200 lines of code and a few kilobytes to thousands of lines of code and multiple megabytes or gigabytes.