I love how Sunny explains the brief history behind technology in his videos, since at times it is a crucial part in the learning process to understand how the technology came to be and why we need it.
I never write comments, but here it goes: Networking topics will be part of my final exam in two weeks and honestly your videos have been such a life saver. I hope you know you're changing lives with your content! Thank you Sir!
Simply brilliant explanation! Your channel is a boon for anyone looking for good CS fundamentals. Keep it up and hope you can publish topics on Core OS concepts as well?
Awesome, Sunny is my to go resource whenever I need to refresh concepts in networking, security and basically IT! Thanks again Sunny for the topnotch content :)
Thank you sir, the pace and simplicity with which you explain concepts is commendable, when In doubt or want to learn about a subject, I search with Sunny Classroom #####, #### stands for whatever network related concept I am looking for, simple and Brilliant
Again, the best explained video I've seen on this. Your videos are excellent. I needed a refresh. I do have a couple of clarifying questions about this. 1) Dynamic NAT - what happens if all the public IP addresses are used up? Are internal hosts denied access to the internet then? 2) PAT - If an internal host sends an outgoing packet on port 80, but the gateway then translates that to port 8001, how does the web server on the internet know you are trying to communicate with it on port 80? Thanks, Sunny.
Here is what I think: 1) Yes, they must be denied access until an available public IP comes out; and if not using PAT. 2) The port 80 of the internal host is NATed. The web server doesn't care about that port but the one that comes by 8001 where it will reply the request. The router-gateway receives by 8001 and translates to 80 to the internal host. The web server will never know you tried by the port 80, and doesn't matter.
Thanks for explaining the differences in the different types of NAT... i was a bit curious how the external unit would know where my request came from, but i think it is by using the PAT by default.
Short and sharp. I learnt alot within a short time. A question here please. If I'm using DNAT to connect, should I forget about PNAT? Or can I use them both simultaneously?
If I understand it uses the TCP port number for uniqueness, now suppose one host using all the available ports (2^16 ports), then how will NATs in the router will map other hosts for incoming traffic?
The truth is that your router typically uses more than just port number to track the socket/session. It uses the source IP, sort port, destination IP, destination port. This combination of 4 data points allows it to keep track of a lot more than 65536 sessions.
@@addanametocontinue The combination in raw is: 2^32 src ips * 2^16 src ports * 2^32 dst ips * 2^16 dst ports = 2^96. But normally it is only used 1 unique public IP so it is: 1 src ip * 2^16 src ports * 2^32 dst ips * 2^16 dst ports = 2^64. But also there are some reserved and private IP that are not used as dst ips; they are about 1/8 (en.wikipedia.org/wiki/Reserved_IP_addresses) of the possible 2^32 . About the dst ports, can be used them all (like for port forwarding to one's PC- server), but normally just a few are used, like 25, 80, 443, 5228. So they may not be 2^16, but let's leave them on these 4. We have 1 srcIP * 2^16 srcPorts * (7/8) 2^32 dstIPs * 4 dstPorts = (7/8)2^50 possible combinations-sessions. They are still a lot. If one user is using a public IP address on its PC, then can use all those ~2^50 combinations. For a single outside-server like Facebook (with single public IP let's say), with same port 443 for example, well then yes it is 1 srcIP * 2^16 srcPorts * 1 dstIP * 1 dstport = 2^16 possible combinations-sessions; it is 65536 sessions, that, to be active, need constant activity, because if not, they expire so srcPorts can be reused. All this implies that they are still so that many so that PAT is possible. Let's say it is not a user's PC with public IP but the router with NAT-PAT -the most common form 6:04-; and that 100 devices are connected to it and all browsing Facebok (with 1 public IP address) in same port 443: They share the 65336 combinations the router can give by assigning srcPorts to them all (very improbable all 100 at same time browsing same web but who knows, though it is about 650 srcPorts for each evenly). The router will translate the internal hosts' IPs (with their ports) to all srcPorts as they are available. If, as @Mohan Gyara stated, only 1 device is exhausting the 65536 (surely only with a virus making source DoS) srcPorts, then surely no way the other 99 devices will be able to browse Facebook... but only Facebook, not all the web; without a virus it is almost imposible for 1 device or even 100 devices to exhaust the 65536 srcPorts to one single dstIP and dstPort, and single public srcIP. If the same device or other devices visit TH-cam, then it is other IP and other possible combinations of 65536 srcPorts with that different dst IP and Port to be written in the router's NAT table.
Is it beneficial to run DNAT on private ips on one intranet? Situations for very large networks that have a lot of remote machines connecting to a central location
Sir Please Discuss Link aggregation Switch, NIC Teaming , and MLAG vs. Stacking, Trunking ,Static Link Aggregation.....Managed and Manage Switch ... Thank you..
I will do soon. Please come back to check my new videos. I will do trunking this week. I put your topics on my to-do list and I will make some videos for your some topics hopefully this month.
1:53 Problem! Default Class B mask is two octets, which is /16 and not the /12 shown in the video. Also, Class C mask is three octets, which is /24, not the /16 shown.
Man0fMeans he is showing the subnet mask for private IP addresses. Class B private range only uses the first 12 bits; the first octet, and 4 from the second octet. Class C private range only uses the first 16 bits, or, the first two octet.
@@davidb1132 I think Man0fMeans is right. Better explained at en.wikipedia.org/wiki/Private_network, the third private range is a Class B or 256 Class C Networks. And the 2nd private network uses 16 Class B, but is not a single Class B.
@@FatimaHassan-fn1vk It is possible with some more advanced software, but we cannot see from our client-side command. Please let me know if you find it.
@@FatimaHassan-fn1vk If you're in a company using a router, you can use the show run command to see all the configuratons made to this router including NAT, of course if you have access to this router. If you're talking about your home private network (WLAN) using a wireless Access point, then you just go to AP's settings page to check the type of NAT you're ISP used for your network.
Greetings to you. Do you need to link the router's internal ip to the router's mac ip address when using Nat feature in order for it to appear to the world? Or link it to the mac ip pc in the restorative section.
Everything is very clear now woooow great vidéo! Is it possible to do NAT by mapping all the adresses in a network to a public ip adress? In fact at the client side i do not know the ip adresses of his servers. i probably know he will not tell me.
Only question is that, (about port forwarding) if router takes ip address from ISP and its DHCP, i mean, the wan side of router always change because of dhcp, how i can connect from outside to internal network? Lets say i have ip cameras which connected to Dvr and it also connected to router, how i can use port forwarding if wan side always change
This is okay but states that PAT is most common but I don't see how it is even useful. It shows 192.168.100.74:80 translated to 234:1.2.33:8001 but if the destination web server is not listening on 8001 then you are not going to get a desirable result.
I love how Sunny explains the brief history behind technology in his videos, since at times it is a crucial part in the learning process to understand how the technology came to be and why we need it.
I never write comments, but here it goes:
Networking topics will be part of my final exam in two weeks and honestly your videos have been such a life saver.
I hope you know you're changing lives with your content! Thank you Sir!
Great to hear!
Thank you sunny, i have been in the field for over 18 years, no one made the concepts so clear for me, You're the best! I like your chenglish toooooo.
Whenever my Udemy instructors are being jive turkeys, I always look up Sunny's Classroom for a clear explanation. This guy is the best!
Simple and very well explained. I get back to Sunny anytime I need to review the basics of any topic. Thanks Sunny!
Thank you Sunny, I have been watching many TH-cam videos but they do not explained this in such a logical and simple way.
Simply brilliant explanation! Your channel is a boon for anyone looking for good CS fundamentals. Keep it up and hope you can publish topics on Core OS concepts as well?
Credits to you fir explaining it in such a clear and easy understanding way, thanks!
You are quite welcome, Steve.
Awesome, Sunny is my to go resource whenever I need to refresh concepts in networking, security and basically IT! Thanks again Sunny for the topnotch content :)
Thanks Sunny.. you explain stuffs so well. Wish I found these lectures during my engineering..😃
You are welcome and thank you for your nice comment.
Thank you sunny , i have gone through all your videos they are well explanatory . you are the Teacher of the century
it's quite interesting how something really helpful and seemingly innoccous has prevented transition to IPV6.
wow man i watched 2 other videos had few open questions, watched your 9 minute video and everything is clear now. You are talented teacher
@Sam Darwin this is a spam
Excellent . No Other video can be better than to explain NAT-PAT
Thank you Sunny, your videos helped me passed a lot of exams
I can't say enough good things about Sunny Classroom.
Best explantion ever. Sunny is better than Google's IT course in exaplaining NAT, no doubt.
Very Nice Explanation. Watched Many. only now all confusions are cleared
Very clear, better than my expensive cissp textbook!
Thank you for watching!
Thank you sir, the pace and simplicity with which you explain concepts is commendable, when In doubt or want to learn about a subject, I search with Sunny Classroom #####, #### stands for whatever network related concept I am looking for, simple and Brilliant
Great video. It is very clear and detailed. Much easier to understand. Thank you Sunny.
You are welcome!
I loved this video. Very high quality explanation.
Thanks a lot or your nice comment.
Thank you for the clear and concise explanation as usual. Your videos taught me a lot!
WE LOVE YOU SUNN!!!! THANKS FOR THIS... AND PLENTY OTHER VIDEOS. I REALLY VALUE THE THINGS YOUVE TAUGHT ME
thank you very much for the videos, so clear, so easy to understand. Hats off 🤩
Hi Sunny Love ur teaching videoes. Thanks for sharing
you are welcome!
Quick, concise and very clear. Thanks!
Again, the best explained video I've seen on this. Your videos are excellent. I needed a refresh. I do have a couple of clarifying questions about this. 1) Dynamic NAT - what happens if all the public IP addresses are used up? Are internal hosts denied access to the internet then? 2) PAT - If an internal host sends an outgoing packet on port 80, but the gateway then translates that to port 8001, how does the web server on the internet know you are trying to communicate with it on port 80? Thanks, Sunny.
Here is what I think: 1) Yes, they must be denied access until an available public IP comes out; and if not using PAT. 2) The port 80 of the internal host is NATed. The web server doesn't care about that port but the one that comes by 8001 where it will reply the request. The router-gateway receives by 8001 and translates to 80 to the internal host. The web server will never know you tried by the port 80, and doesn't matter.
Very useful video, easy to understand and remember. Great job! Many thanks!
You are welcome!
Simple and easy to understand... thank you
Thanks for explaining the differences in the different types of NAT... i was a bit curious how the external unit would know where my request came from, but i think it is by using the PAT by default.
Watching our videos always makes my mind feel less stress .
A really good explanation, well paced and clear. Thank you
This is awesome! Thanks for the precision and detail, Sunny.
Best on the web explanation. thanks bud
Wonderful explaining my teacher. Thank you so much
Thats a Beautiful Explanation with some Graphics to explain
Glad it was helpful!
@@sunnyclassroom24 can you explain dmvpn the same way along with configuration? Is there a video tutorial already for dmvpn?
You deserve more subscribers, this is awesome
you are wonderful teacher.
At last I understood. Thank you sunny!
Awesome!!
You are so amazing tutor
Thanks a lot!
Excellent video. Extremelyt Informative. Subscribed!
Short and sharp. I learnt alot within a short time.
A question here please.
If I'm using DNAT to connect, should I forget about PNAT? Or can I use them both simultaneously?
Very good Sunny! Thanks for making this video
Thank you! Very good explanation.
Excellent. Thank you.
You are welcome!
best explanation of NAT can you tell me which editor are you used for these type of videos
Great video! Thanks!
Thanks you for watching!
Awesome Video Sunny , Well Explained !!!
Another perfect video... Thanks Sunny
very great explainations about this 🤗🤗🤗
excellent videos! you should start patreon i'm sure lot of people want to donate to you for the excellent videos.
Awesome explanations!!!!!!
Very well explaination, thanks
You re welcome !
How amazing this explanation was!! 😀
Glad it was helpful!
Very good Sunny
Very nice explanation with animations sir, thanks. Therefore, you got me as subscriber. Do you also teach ethical hacking?
Love you sunny. such helpful vidz
BRO I LOVE SUNNY
If I understand it uses the TCP port number for uniqueness, now suppose one host using all the available ports (2^16 ports), then how will NATs in the router will map other hosts for incoming traffic?
The truth is that your router typically uses more than just port number to track the socket/session. It uses the source IP, sort port, destination IP, destination port. This combination of 4 data points allows it to keep track of a lot more than 65536 sessions.
@@addanametocontinue The combination in raw is: 2^32 src ips * 2^16 src ports * 2^32 dst ips * 2^16 dst ports = 2^96. But normally it is only used 1 unique public IP so it is: 1 src ip * 2^16 src ports * 2^32 dst ips * 2^16 dst ports = 2^64. But also there are some reserved and private IP that are not used as dst ips; they are about 1/8 (en.wikipedia.org/wiki/Reserved_IP_addresses) of the possible 2^32 . About the dst ports, can be used them all (like for port forwarding to one's PC- server), but normally just a few are used, like 25, 80, 443, 5228. So they may not be 2^16, but let's leave them on these 4. We have 1 srcIP * 2^16 srcPorts * (7/8) 2^32 dstIPs * 4 dstPorts = (7/8)2^50 possible combinations-sessions. They are still a lot.
If one user is using a public IP address on its PC, then can use all those ~2^50 combinations. For a single outside-server like Facebook (with single public IP let's say), with same port 443 for example, well then yes it is 1 srcIP * 2^16 srcPorts * 1 dstIP * 1 dstport = 2^16 possible combinations-sessions; it is 65536 sessions, that, to be active, need constant activity, because if not, they expire so srcPorts can be reused. All this implies that they are still so that many so that PAT is possible. Let's say it is not a user's PC with public IP but the router with NAT-PAT -the most common form 6:04-; and that 100 devices are connected to it and all browsing Facebok (with 1 public IP address) in same port 443: They share the 65336 combinations the router can give by assigning srcPorts to them all (very improbable all 100 at same time browsing same web but who knows, though it is about 650 srcPorts for each evenly). The router will translate the internal hosts' IPs (with their ports) to all srcPorts as they are available. If, as @Mohan Gyara stated, only 1 device is exhausting the 65536 (surely only with a virus making source DoS) srcPorts, then surely no way the other 99 devices will be able to browse Facebook... but only Facebook, not all the web; without a virus it is almost imposible for 1 device or even 100 devices to exhaust the 65536 srcPorts to one single dstIP and dstPort, and single public srcIP. If the same device or other devices visit TH-cam, then it is other IP and other possible combinations of 65536 srcPorts with that different dst IP and Port to be written in the router's NAT table.
I decided to configure NAT on my ZTE MF29A router but NAT Feature is not present on the Router interface. How do I do it
(AT 4.30)
DNAT does not deal with outbound traffic, it deals with inbound traffic. SNAT deals with outbound traffic
Very clear, thank you
Thanks a lot.
I have see SNAT defined as
Source NAT
Secure NAT
Static NAT
thanks a lot brother sunny.
Really great video!
Thanks for the explanation! your Videos are great!
You are welcome! Thank you for your time! Check out my other videos please!
Great explanation!
Hi, great video... do you have any videos on symmetric NAT? Or a clear explanation?
Is it beneficial to run DNAT on private ips on one intranet? Situations for very large networks that have a lot of remote machines connecting to a central location
Sir Please Discuss Link aggregation Switch, NIC Teaming , and MLAG
vs. Stacking, Trunking ,Static Link Aggregation.....Managed and Manage
Switch ... Thank you..
I will do soon. Please come back to check my new videos. I will do trunking this week. I put your topics on my to-do list and I will make some videos for your some topics hopefully this month.
I does not forgot to subscribe😌
Mavaaa nuvu super
hi great u have shown from 24 but how to calculate from like example of subnet 10.0.0.0/16 could u explain please
You are SOOOO AMAZING 🔥🔥🔥🔥
1:53 Problem! Default Class B mask is two octets, which is /16 and not the /12 shown in the video. Also, Class C mask is three octets, which is /24, not the /16 shown.
Man0fMeans he is showing the subnet mask for private IP addresses. Class B private range only uses the first 12 bits; the first octet, and 4 from the second octet. Class C private range only uses the first 16 bits, or, the first two octet.
@@davidb1132 I think Man0fMeans is right. Better explained at en.wikipedia.org/wiki/Private_network, the third private range is a Class B or 256 Class C Networks. And the 2nd private network uses 16 Class B, but is not a single Class B.
this is great effort .. keep up the great work.
Than you for your nice comments!
thank u master...
thank you sooo much sir
This is amazing!
Thank you!
Thank you Sunny!
Do we commonly use PATs or DNATs in our LAN networks?
It depends on the size of the organization and its service.
Isnt there any way of knowing which NAT we use through the ipconfig/all command or by typing any other command in the terminal?
@@FatimaHassan-fn1vk It is possible with some more advanced software, but we cannot see from our client-side command. Please let me know if you find it.
@@FatimaHassan-fn1vk
If you're in a company using a router, you can use the show run command to see all the configuratons made to this router including NAT, of course if you have access to this router.
If you're talking about your home private network (WLAN) using a wireless Access point, then you just go to AP's settings page to check the type of NAT you're ISP used for your network.
Great content. Thank you.
Thanks a lot
Greetings to you. Do you need to link the router's internal ip to the router's mac ip address when using Nat feature in order for it to appear to the world? Or link it to the mac ip pc in the restorative section.
Nice explanation
Everything is very clear now woooow great vidéo! Is it possible to do NAT by mapping all the adresses in a network to a public ip adress? In fact at the client side i do not know the ip adresses of his servers. i probably know he will not tell me.
Subscribed to your Channel Sunny .
You are awesome
perfect thanks!
you are welcome!
Thank you so much!
You are welcome!
subscribed and liked!😄
Only question is that, (about port forwarding) if router takes ip address from ISP and its DHCP, i mean, the wan side of router always change because of dhcp, how i can connect from outside to internal network? Lets say i have ip cameras which connected to Dvr and it also connected to router, how i can use port forwarding if wan side always change
Using DDNS
Pls create a separate video on patting. Since it's not clear from your previous video
This is okay but states that PAT is most common but I don't see how it is even useful. It shows 192.168.100.74:80 translated to 234:1.2.33:8001 but if the destination web server is not listening on 8001 then you are not going to get a desirable result.
Sunny sir please upload same on D-Link switch
what is the arrow meaning? how is it called?
arrows means here an IP address is translated into another IP address. That is basically what NAT is all about.
Turn the speed to 1.25. Thank me later
Thanks
Thank you!
What is there to thank? I'm pretty sure people know how to turn their speed preference without an idiotic account saying so.
later
Thank you!
Watched this video at x1.25 speed. it's 1000 times better.
Thank u❤️❤️
You are welcome!