Dynamic NAT - Network Address Translation

Dynamic NAT is a type of translation that allows many internal hosts to share fewer external IP addresses. Typically in today's world, a true Dynamic NAT is very rarely used. However... Dynamic NAT is often confused with a Dynamic PAT -- which *is* used very commonly.

The critical difference between a Dynamic NAT and a Dynamic PAT is with a Dynamic NAT, the IP address can only be used by one internal host at a time... where as with a Dynamic PAT, the IP address can be shared among many internal hosts at a time.

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00:00 - Dynamic NAT definition
01:01 - Dynamic NAT Illustration & Configuration
01:35 - Dynamic NAT Packet Flow
04:15 - Dynamic NAT is Bidirectional
05:04 - File Transfer Protocol -- Active FTP vs Passive FTP
07:30 - Lazy Static NAT
08:58 - Disadvantages of Dynamic NAT
10:22 - Summary + Dynamic NAT vs Dynamic PAT

#dynamicnat #pat #nat #rfc1918 #ip-address #cisco #juniper #ccna #net+ #dynamicpat

[rotrose]

Your channel provides the best, most easy to understand networking content to all of us. I can not say enough thanks.

[moonlightknight]

Thank you for creating such amazing videos. Your videos have been a lifesaver for me. I was not understanding NAT vs PAT until I watched this series.

[VideosfromElle]

Just such a great, consistent, valuable delivery!

[Demopanz]

Terrific video to help explain what i am reading in my network+ book. Thanks for having this sort of stuff easily available

[simonsays]

Waiting for the complete networking course !! Great content as always !

[nickjurkovic]

Amazing, this is actually fun to watch :)

[justsomebody]

Thanks so much for your work! It helps me so much! You're the best channel on network topic i ever saw!

[neill]

9:30 you said that one of the disadvantages of dynamic NAT is non deterministic IP assignments which can cause a problem when trying to configure an ACL.
Isn't the configuration of an ACL based on private IP addresses and not on public ones?

[skalmelid]

In your ftp example. At 5:47 when opening the second channel, did you actually mean a different random port than the control channel is using? You called them both R.

[fajarhariadi]

how can the router have multiple public ip address? do each ip have their own port and cable to the public, or using sub-interface? and did they need to be in the same subnet, or it can be done with different subnet of public ip address?

[johnnydepp]

Have a complete networking course please

[aaronnikels]

Hi, thanks for the fantastic content! I have a question about FTP I was hoping you could answer...

Why does FTP initiate a new connection over port 20? Why not just respond with the data over port 21? Why make this entirely new connection if you can just use the same channel? Also, even if FTP uses port 21 anyways, why not address the packet to the same temporary port that the request was received from? If Active FTP cannot work with dynamic PAT, then that means it is attempting to send data to a new port on the local host, otherwise if it was sent to the same port that initiated the connection on the router's public IP, the router should be able to locate the entry on its routing table and translate it. Why not just use the same port that the request was sent from over port 21 on the control channel? I know Active FTP is legacy, but it sounded like passive FTP had the client initiating both connections, and I just don't see why the server couldn't just respond with the data either over the same port or just send the data from a different port (i.e. port 20) to the same port the client requested it from, that way the client wouldn't be initiating new connections and it would just be a lot more consistent

Either way, great video! Your explanations are always very clear and easy to understand