this post was submitted on 19 Apr 2024
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Whether you're really passionate about RPC, MQTT, Matrix or wayland, tell us more about the protocols or open standards you have strong opinions on!

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[–] Badabinski@kbin.social 6 points 7 months ago* (last edited 7 months ago) (20 children)

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.

[–] Badabinski@kbin.social 7 points 7 months ago* (last edited 7 months ago) (19 children)

PART 4.

You expect a file transfer program to reliably and faithfully transfer your files, byte-for-byte, from one system to another. FTP spits in your face and shits on your chest. You know how Linux uses LF (i.e. \n) for newlines and Windows uses CRLF (i.e. \r\n) for newlines? Pretty annoying, right? Well, FTP's ASCII mode will automatically rip off those \r characters for you! Sounds pretty sweet, right? Fuck no it's not. All of the sudden, your file checksums have changed. If you pass the same file back to a Windows user with a different and more sane file transfer system, then they get a broken file because FTP didn't mind its own fucking business. If you have a CRLF file and need an LF file, just explicitly use dos2unix. Wanna go the other way? unix2dos. The tool has been around since 1989 and it's great.

Now, what if you're not transferring text, but instead are transferring a picture of a cute cat? What if your binary data happens to have 0x0D0x0A somewhere in it? Well, ASCII mode will happily translate that to 0x0A and fucking ruin your adorable cat picture that you were going to share with your depressed significant other in an attempt to cheer them up. Now the ruined JPEG will remind them of the futility of their situation and they'll slide even deeper into cold emptiness. Thanks, FTP.

You can tell your client to use binary mode and this problem goes away! In fact, modern clients do this automatically so your SO gets to see the adorable fuzzy cat picture. But let's just stop and think about this. Why use a protocol that is dangerous by default? Why use a protocol that supports no form of security (unless you're using fucking godawful FTPS or FTP over SSH)? Why use a protocol that is so broken by design that small business hardware has been designed to try to unfuck it? Is it faster? I mean, not really. SFTP has encryption/decryption overhead, but your CPU is so fast that you'd need to transfer at 25+ Gb/s to notice it. Is it easier? Fuck no it's not easier, look at all of the stupid footguns I've just mentioned. Is it simpler? The line protocol is simple, but so is HTTP, and HTTP has a much simpler control flow path (merging the data and control planes is objectively the right thing to do in this context). And shit, you want a simple protocol for cases where you don't have a lot of CPU power? Use fucking TFTP. It's dogshit, but it was intentionally designed to be dogshit so that a fucking potato could receive data with it.

There is no task that is currently being done with FTP that couldn't be done more easily, more securely, and more quickly with some other protocol (like fucking SSH and SFTP, which is now built into fucking Windows for god's sake). Fuck FTP.

[–] aksdb@lemmy.world 2 points 7 months ago (1 children)

Have you considered publishing that as a book? (/s)

You are insane... in a good way. I love it. Fantastic read and I had to chuckle a few times.

[–] Badabinski@kbin.social 1 points 7 months ago

I'm glad that my grumpy migraine ramblings brought someone some joy!

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