Network Address Translation - Computerphile

You guys are my heroes, me who has no computer science background but I am learning how to develop softwares by myself. These videos are extremely helpful. God bless you all

Finally, a rational, clear explanation of how NAT works and how it's implemented. Thanks !!

poorly explained

Now I understand why admissions are difficult in top universities.
Because the quality and the way of explanation is so damn good!!!

Age of empires, anyone?

this is great, the cissp textbook only explains how ip addresses are translated but never mentioned port number translation.

thanks sir that was so clear

Can you please make a video on CIDR Notation!

Great video as always. But, boost up the volume a bit, hardly able to hear.

Thanks for your videos

University of Notingham is awesome. you guys have conversant professors! I also love Nottingham for the fact that Robbin lived there!! Regards from Sri Lanka.

To put it a little simpler, imagine your house with 10 devices on the internet (laptops, desktops, game consoles, etc). Those don't have their own external IP address (the one on the internet). You only have 1 for your modem/router, and your router then forwards a packet to each device based on the port # and internal IP address.

This is why you need to set up port forwarding if you've ever played an online game, so that when a packet hits your router on a certain port, it knows which computer to send it to

his analogy was kinda unrelated or wrong. If something in the application layer refered the ip address, it is breaking the abstraction layers. The software should have referenced its location abstractly in the abstraction layer. But then NAT is wrong for requiring ip and tcp or udp layers. But unrelated to what he talked about.

But, this will only hold out for so long. IPv6 has many benefits over IPv4, besides more addresses.

NAT sounds more complicated than introducing IPv6 to me. Doesn't global use of NAT also require changes in the software of lots of devices (like what in this video is called the gateway of a home or university campus network), just like introducing IPv6 would?

nice, keep up the good work computerphile

What tools did you use for creating this animation? Amazing!

Sooo, this 10 minute discussion of NAT made way more sense then the 1 week discussion of the same topic in my networks course at my university. I'm not sure how I feel about that

Hence the need to use ipconfig /renew in Win cmd all the time.

can you please amplify the voice data? hardly able to hear.

Port forwarding. Now I understand you :)))

how do i switch my strict nat type to open?... my ps4 says that my router has a nat type of 2 but when i go to play games it says my ant type is strict and i cant connect to my friends.. i dont get it...

The first time I ran into a NAT problem I was trying to host a Warcraft 3 map online. Port forwardings at my router didn't work, I had to use something called "port triggering".

Brady, it would be helpful to have a video focused on NAT or IPv6, or port-forwarding. I've been trying to solve a networking problem: connecting from a remote unix machine (a laptop--meaning I could be anywhere) to a database engine (SQL server) residing on my home network. I've learned more about networking than I ever wanted to know--just in tinkering to get to my database! But now I'm intrigued...

Every single computer in the world needs upgrading by 2038. Computers need to all be 64bit by then, because of the way time works. The upgrades will come.

With the arrival of IP6, (and lets laugh at the thought that the world all moves over to it eventually), would this be the end of NAT/PAT's needed? Is there an advantage/disadvantage to each home PC having a unique IP address and not a private internal one? I as this as a Small Company / Home user point of view.

what he explained was overloading, or PAT(port address translation). But it was still a very nice explanation of PAT. just clarifying.

My engineering brain just broke and had an orgasm at the same damn time.

It works, but not for all protocols, for example, FTP uses two connections - one for control and one for data, the server sends its IP/port over the control connection and the client connects to it (passive mode). Now the FTP server software has to be modified to figure its external IP first. Some routers can rewrite te IP in the packet, but not for all protocols (and not for encrypted connections). However, NAT has other uses than just to save some IP addresses.

Ehh port forwarding someone?

this guy gave me a lecture at the Uni

The image has the .jpg extension, it must be an animated GIF disguised as a JPEG. Clever.

Something he did not explain very well is that the relabeling is only done in the Source port when the packet is going out and that when it packet arrives back, that "fake relabled port" is now on the destination port. The reason being google (for instance) still needs to know that the packet is going to port 80, receiving "18" would not work as the packet would be rejected.

hmmm

one guy purchased comp parts on ebay. But it was junk parts. The seller hacked the buyers comp and distroyed some inside parts shuting it down. Its a nightmare of pre-engineered failures needing continual maintanance to there benifit and your misfortune. EVIL.

thanks...thank you very much that clears things up a lot

Yous should do a video on minecraft computers ;)

that'd be me

Who the fuck is this Sean Riley guy??

Moving to IPV6 is a tremendous challenge because a lot of older routers/network devices don't support IPV6. TO suddenly mandate everyone use it would be a disaster. NAT is basically extending ipv4 capacity, the same a hotel extends it's phone network capacity by giving every room an extension number rather than an actual phone line.

Better than most my professors and lecturers

No. Just no.

No, it's not Brady filming these.

The Cameraman...Brady Haran -.-

My nat is closed. ): Always.

I'm cool with never adopting IPv6. Hooray for NAT. =)

IPv5 wasn't skipped it was given to the Internet Stream Protocol sometime in the late 70's which never saw widespread adoption. So when a new Internet Protocol was being designed it was assigned the next version number - IPv6

We have IPv6 (v5 was skipped?) which allows for as MUCH larger pool of addresses. Many modern OSes and routers support it, but numerous older ones do not and some ISPs appear to be slow in implementing it.

so we basically need to make IPV5 so that we will have several times the capacity, we just need to make the move, we have to upgrade computers soon enough anyways because the internal clocks are counting down