IPv6: Fuck you, you’re only allowed one, now. Yeah, yeah, I know there are about 340 undecillion addresses in the space, but I know better than you, no one in history has ever needed to bind different services to the same port on the loopback interface, and if they did they were doing it wrong. Oh you made an RFC draft? Well I let the one from 2015 expire, so good luck with your current proposal, pleb.

Subnet Masks are how you get networks. It’s simple binary ANDing math.

For example, if you have a 192.168.1.1 IP address and a subnet mask of 255.255.255.0, that means the first 3 octets (each block of numbers between the dots representing an 8 bit value) of 255 are the network part of the IP (192.168.1.0/24) and the fourth octet is the host addresses space of the address. It’s saying 192.168.1 is the network and the last number is the host on that network.

If you take 1 from 192.168.1.X and convert it to binary, you get 00000001. If you convert 255 to binary, you get 11111111.

If you line them up and “AND” them together sort of like you’re adding them together in a “both must be true” comparison, you get

00000001

11111111

00000001

A 1 and a 1 makes 1. Anything else makes a 0. Basically the 192 gets ANDed to 255 and comes out as itself. Same for 168 and 1.

For a 255.0.0.0 (or /8) 255.255.0.0 (or /16), and 255.255.255.0 (or /24) it’s easy, because it’s all 1s or 0s for each block of 8 bits of the 32 bits that make up an IPv4 address. Each block just plops out as itself because it’s all 1s or all 0s for each of the 4 blocks.

Now try that with 23 bits instead of 24.

00000001 for the third octet “1” part of 192.168.1.1

11111110 for “254” part of 255.255.254.0 (aka a /23)

00000000 or 0 for the third octet.

This means that the network ID is 192.168.0.0/23 and the usable IP addresses are 192.168.0.1 through 192.168.1.254.

With a /23 network, you get 512 addresses instead of 256 with a /24 (192.168.0.0-192.168.1.256 versus 1.0 through 1.256). The first IP is the network ID and the last is the broadcast address, both of which are unusable, so you have 510 IP addresses in a /23 to use for devices instead of 254 with a /24.

This is how basic IPv4 subnetting works and it’s how you size various networks for things like Enterprise that needs more than a small home network of less than 254 devices.

Congrats. If you understood that, you now have enough knowledge to probably pass some network exams.

It tells you how to read the IP address. It’s a really cool trick that’s an enormous pain in the ass.

Wait is there an existing unicode to ipv6 method. I assume it would just be the bit values of the emoji in utf8?

fe80::“hello 🐔” aka fe80::6865:6c6c:6f20:f09f:9094

I approve of the idea of cursed ipv6 notation.

sup

Settle down, Satan.

oh my god

i love this idea so much. I’ve been doing networking for 13 years now and I’ve never considered a dynamically addressed gateway

About twenty years ago I was hired in to straighten up a network at a investment place. They were running all static IP addresses and the guy who set it up set the gateway to 69. I laughed and started converting them to dhcp and seriously considered leaving the gateway alone.

I have to ask a question now. My question is, is that you?

The “gateway” is 69. Noted

Gateway has multiple IP addresses, from .1 through .10 . (I used to have multiple OpenWRT servers for different things, but consolidated them all into a single rackmount server.)

Back before i knew anything about networking and set my desktops with statics, i had .1-9 as user devices, .10-19 as servers, .20-29 as printers, .50-59 as networking devices. So my current server is .14 and has been that since uni, DNS is .50, gateway is .51. Now my dhcp pool starts at 100.

DHCP gave me 170. I said “let’s make this static shall we?”

Lol mine is .116 for the same reason

Lol, same-ish, lazy gang ftw.

That’s the kind of overengineering I was hoping for!

Nothing advertises hostnames, and the DHCP table is dumped and every client gets new address at the same time, too.

Just make sure the MAC addresses randomize, too, and then you’ve got yourself a proper fucking mess for a hacker to sort out.

I use 10.13.37.42 as my gateway.

A typical ip address scheme is to assign lower blocks to dhcp pools and reserve high ip addresses to servers and network gear. Anything over 250 is typically a switch or a router in this case.

I’ve had modems from my ISP which assigned themselves 192.168.0.254 for some reason. I have no idea why

It’s called multicast edit: broadcast and it’s for spamming every device on the network /s

10.10.0.254 here, because I wanted my main rig to be .1

I work for a French company that does this, I don’t know if all French companies do this, but it threw me for a loop for sure.

Settle down Satan

So statically assign all IPs except for your gateway?

*First Usable Address. Obviously u can drop the usable part.

This guy networks

Literally seen this in the real world too.

RIP