IP Addresses and the Internet - Computerphile

IP addresses explained - what do these mysterious numbers and dots mean and how are they used? Richard Mortier explains the idea of the addresses behind the internet protocol.

This video was filmed and edited by Sean Riley.

[Lozlesndstuff]

These videos are awesome! Keep doing what you're doing

[Computerphile]

Yes, apologies, an unfinished version went live by mistake (my mistake) >Sean

[PeterWalkerHPc]

I wrote a command line TCP and route table utility a few years ago and occasionally it failed during testing. Eventually a fellow developer noticed that the occasionally input values did not match the debug values.

Lesson - don't ever put leading zeros in dotted quad for the sockets library, it treats it as bloody *octal!!* even for ping!

[BatteryAcid]

Great vid! Very informative and well explained.

[uimasterskill]

Brady, I would really love to see a video about the whole DNS and who how is it organised and how do domain name providing sites essentially enter their users' requests into the DNS. I really hope it will be coming in the future... please? :)

[xanderlander]

Having studied computer networking in college I can say this is pretty accurate. It's not the whole picture, in fact it glosses over and leaves out a lot of stuff, but it has to do ths in order to keep the length of the video short and the information easy to understand. Nice job guys!

[DFPercush]

192.168 is a special prefix for class C subnets - local networks which have < 255 computers. It's used as the local address of your computer when it's behind a NAT router (most home routers are). No public addresses are assigned from this pool, so anything with 192.168 automatically points to something on the local network. The 1.1 part is just convention, but it usually means the gateway or router in your building. It can be changed in DHCP settings on the router.

[mastermax]

BEST CHANNEL EVER!! GO GO GO show advanced stuff

[iabervon]

The upcoming NAT video will help to explain it. Since there aren't enough IPv4 addresses for every computer, addresses that start with 192.168 get reused for different computers that can't talk directly to each other (likewise, addresses that start with 10). These addresses identify unique computers on a LAN, and NAT handles getting packets between the internet and your LAN.

[Hanoverflow]

Thank you for the videos Riley I really like your channels

[Computerphile]

Apologies to those who may have seen this posted twice - slight technical hitch yesterday >Sean

[fishdoneraw]

Hi Computerphile, could you maybe please make a video about the various programming languages; a brief history, their uses today, and key programming languages to know for the future? thanks!

[DoctorCobweb]

can u please post the NAT video soon? looking forward to it.

[svommams]

There were many different attempts at creating a successor to v4. Some of them didn't work out, but have already been assigned version numbers 7, 8, and 9. The next available number for a successor to version 6 is version number 10. And we better get it right that time, because the version numbers run out at 14.

But IPv6 has so many addresses, that we are more likely to need a new version due to lack of support for interstellar communication than due to lack of addresses.

[oWhiteMonster]

IPv6 addresses are represented as eight groups of four hexadecimal digits separated by colons, for example 2001:0db8:85a3:0042:1000:8a2e:0370:7334, but methods of abbreviation of this full notation exist.

[zanfur]

The "version header" is the number of the protocol, not the version of IP itself. The RFC section you reference states only that it describes the header, and that the number is 4. It's used by the frame layer underneath IP. Version 5, for example, was a streaming protocol. Numbers 4 through 9 are allocated. See RFC1700, which describes the purpose of of that field as to identify the version of the "internetwork general protocol"...which is not "internet protocol". but a superset of it.

[AdmiralMaur]

Computerphile. Could you do a video on the history of Arpanet and Darpanet? Basically a history lesson on what has become the internet.

[robbie]

No, that's not reserved for the same thing at all. According to rfc6598, "Shared Address Space can only be
used in Service Provider networks or on routing equipment that is
able to do address translation across router interfaces when the
addresses are identical on two different interfaces."

[jndominica]

Try to memorize and type in the IPv6 prefix and host numbers of your network like you did just now with IPv4. I feel more comfortable that I can access my system from outside using four small numbers, as well as with the implicit security of NAT. Not all computers and especially "devices" and "things" need a public IP if they don't run servers. Maybe the university of Nottingham could do with less than 60 thousand as well.

[svommams]

That may have been said before, but it is not correct. All versions 1 through 4 were experimental. It just happened that at version 4 it was working so well it spread way beyond expectation. What happened before version 4 is mostly forgotten.

Version number 5 was used for a completely different purpose. It was not some experimental replacement for version 4. But since it had been used, the successor to version 4 had to be assign version number 6.