782
votes
3answers
152k views

Transatlantic ping faster than sending a pixel to the screen?

John Carmack tweeted,I can send an IP packet to Europe faster than I can send a pixel to the screen. How f’d up is that?And if this weren’t John Carmack, I’d file it under “the interwebs being ...
177
votes
7answers
438k views

How can I list all IPs in the connected network, through Terminal preferably?

Using Ubuntu 10.10, I was wondering if there was a command line command that can list all the IPs of devices connected to the network?I would use this for example, to list all the computers ...
116
votes
13answers
78k views

What is the exact use of a MAC address?

I understand that IP addresses are hierarchical, so that routers throughout the internet know which direction to forward a packet. With MAC addresses, there is no hierarchy, and thus packet forwarding ...
85
votes
2answers
15k views

Why does Qatar use a single IP address when 800,000 IP addresses are allocated to it?

In discussions about IP address banning, IP 82.148.97.69 is often cited as an example. According to Wikipedia, this IP address is the public address of "the entire nation of Qatar". There are two ...
82
votes
9answers
16k views

Can you grab any IP address on the Internet?

On a personal network (LAN) one can simply grab an IP address. If you choose the same IP address as an existing client, you get problems. There are companies like IANA and ICANN that are in charge of ...
82
votes
8answers
15k views

IP address that is the equivalent of /dev/null

Is there an IP address that would result in any packet sent to be ignored (blackholed)?I know I can always set up a router with an IP address and then just have it ignore all packets sent to it, but ...
81
votes
10answers
16k views

Are IP addresses with and without leading zeroes the same?

I have a security system and the network setting only allows a three-digit IP address. I can't set it to 192.168.2.100, instead I have to use 192.168.002.100.Are these two IP addresses different? Do ...
75
votes
6answers
41k views

Why is localhost IP 127.0.0.1?

I wondered what is the origin of the decision to make localhost's IP address 127.0.0.1. What is the "meaning" of 127? what is the "meaning" of 0.0.1?
63
votes
4answers
7k views

How do web servers know whether you're using direct IP address access?

Some web servers, when accessed using their IP address, return an error that direct IP address access is not allowed.I've been wondering for some time how this works. I mean, doesn't the browser ...
45
votes
9answers
6k views

Why are subnet-masks relevant for the individual computer on the network?

I understand how subnet-masks are used to divide a network into sub-networks, but, why does every computer in the network need to know the subnet-mask and not just the router? I could understand it, ...
38
votes
5answers
3k views

What keeps you from changing your public IP address and wreaking havok?

An interesting question was asked of me and I did not know what to answer. So I'll ask here.Let's say I subscribed to an ISP and I'm using cable internet access. The ISP gives me a public IP address ...
35
votes
5answers
8k views

How can every single device on a network have a different public IP?

I'm at a computer camp, and I noticed that every single device connected to the network has a different public IP, which really surprised me. What is even more strange is that their public IPs are ...
31
votes
9answers
141k views

Find an unknown static IP + subnet mask of device?

I have a device set with a static IP and subnet mask. I do not know the IP or subnet mask. How can I find the devices IP and subnet mask?It is a piece of hardware, not a PC. It will not take an IP ...
26
votes
3answers
5k views

Why does searching “0.693” bring me to “0.0.2.181”? [duplicate]

While working on math, I encountered a number and wondered if it had any significance. So, in the browser search bar I entered it ("0.693"). I got redirected to the IP address 0.0.2.181, which ...
25
votes
2answers
85k views

How to route only specific subnet (source ip) to a particular interface?

How to route only specific subnet (source ip) to a particular interface?OS: LinuxI know I can do easily by destination IP by using something like route add 1.2.3.4/24 dev eth4 but I do not ...

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