Port Numbers Explained | Cisco CCNA 200-301

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In the last video, we looked at the layer 4 protocols TCP and UDP. Layer 4 is also responsible for choosing port numbers.
So why do we need port numbers? The example I give here is the postal service. To get post, you install a letterbox (at least here in the UK). This letterbox allows the postal service to access your home.
Network applications work in the same way. If you want to communicate over a network, you must allow some means of access to your device.
Let's say we want to access a web server. We type in the web address (also known as a URL) of the site we want to visit.
The first thing the computer does it convert that URL to an IP address.
This is done by using DNS, but we will cover than in another video. For now, just know it coverts web addresses to IP addresses.
The computer then sends the request to the webserver. The server will then look at the destination port to find out which application to send this data to. It can do this because there is a standard that port numbers follow.
When we made our web request, our computer knew we were trying to access a HTTP site. So it added the destination port number 80 to the TCP header.
The computer will also choose a randomly generated source port to receive reply’s on.
Several port numbers are called well-known ports. These are common protocols that have been assigned port numbers.
Examples of well-known port numbers are HTTP(80), HTTPS(443), SMTP (25).
0 - 1023: Well-known port numbers.
1024 - 49151: Registered ports that companies have registered IANA
49152-65535: Dynamic ports
Resources:
tools.ietf.org/html/rfc6335
www.iana.org/assignments/serv...
#ccna #cisco #networking

[@user-or7ji5hv8y]

Wow, I don’t know why others can’t explain this basic idea clearly. Thank you.

[@Certbros]

Thanks! Great to hear you liked the video. Thanks for watching!

[@sharmarkenur8398]

thanks i got point

[@ngatijanoke6311]

F::5

[@hassanahmedsiddiqui5260]

@Certbros Sir how can I find port on my window 10 laptop

[@dandele123]

Letting you know that I passed my CCNA 200-301 this week and your videos helped me do it! Thank you!

[@Certbros]

Congratulations!! These are the comments I love the most!! Nice work 👍

[@radtzerthecommanda8523]

I just begun my course with cisco so i will be a tier 2 engineer

[@christinalahey327]

Thank you! My teacher has made port numbers sound like something that one can only understand with multiple doctorates

[@Certbros]

Thanks Christina! Great to hear the video helped you out. Port numbers are pretty simple once you get your head around it.

[@MathoAvito]

LOL. true story!

[@asit3061]

🤣🤣

[@becks3six9]

🤣🤣🤣🤣🤣 comment is so underrated

[@bwood6337]

Thanks!
Everyone else only explained how ports are used without getting into what they actually are or how they operate which made it a lot harder to really wrap my head around them.
You provided a really great balance of explaining that without getting overly complicated.

[@berbid9051]

Never heard this simple yet comprehensive explanation in any of my computer classes in university.
Thanks for this great video

[@JoseRuiz-mf8zb]

This video made my life so much easier, I just spent a whole semester of just reading and reading and reading, and I literally learned more in this video than the whole semester

[@mrgigs08]

I absolutely like your explanation guys! Keep on doing an amazing job!

[@fudoshin2776]

THANK YOU SO MUCH!!!! I was struggling with Ports but you just explained it so easily. Thanks again 🙏 💕

[@Certbros]

You're welcome! Great to hear it helped 👍Let me know if you have any questions.

[@flamey4446]

@@Certbros thanks now I can boot people yay🤟🤟

[@rishithilak2627]

sir you are the perfect teacher ever i have seen you giving an every real time example for each topic this makes me practically strong.loved your teaching

[@thelowertimeframes1442]

Yes! Port numbers, came at a a great time. If you guys would make a video on Cryptography or Encryption, it would be too great!

[@Certbros]

Thanks Ron. Glad the video helped. Good suggestion. I plan on making some security videos in the future. 👍

[@moneymaker3400]

Best video for this concept in the whole TH-cam.....love you guys❤️

[@tokinabo]

wow, a clear nice voice, at digestible pace, with in depth detailed and yet simple explanation!
hard to come across those days..

[@tanzeelazam9552]

You truly deserve more likes and views. Arigato!!!

[@Certbros]

Thanks Tanzeel! Great to hear you liked the video 👍

[@Randumb96]

These videos have really helped me wrap my head around so many networking concepts

[@1leggeddog]

I've been in IT for 20 years and I still learned something from this.
Never did get my ccna certificate, i just had to learn as I went after college

[@TeamEnneser]

You nailed it. A neat presentation.

[@andrewdelave]

This was the best explanation I've come across by far. Thank you!

[@Certbros]

Thanks Andrew! Glad it was helpful 👍

[@Malitubee]

Bro literally why can’t anyone else just explain it just as easy as you did ! You made this click instantly ,it felt like everyone else was speaking a completely different language

[@MathoAvito]

Thank you so much for the great explanation!
The best sentence in this video was "IP address gets the data to the computer, but it's the port number that gets the right application"
Wrote it down for myself.

[@lawlietnao_music]

Beautiful explanation, thank you so much for your hard work!

[@Certbros]

You're welcome! Thanks for the comment 👍

[@thatguyluffy4941]

Crystal clear on the basics ! good explanation with the figures

[@Certbros]

Thank you!

[@lilianapatarroyo6432]

Thank you! You explained so clearly.

[@conorbase7776]

This is a really informative and fruitful video. I nearly took notes for every sentence in the video.

[@Certbros]

Thank you Conor! Glad I could help!

[@volcanoab4419]

Brilliant ... absolutely the best!!

[@cathydowns5442]

Einfach wunderbar erklärt! Danke...

[@user-ni4fs5pb3q]

I really enjoy and learn well from your videos . Watching your videos is great. :)) Thank you!

[@luckyplay9919]

This was so helpful!! Thank you

[@mehdiroudeau8809]

i am from france and I still understand your explanation better than my own teacher thanks a lot m8

[@jeffhirshberg5171]

😊😊😊😊😊😊

[@shrutijain4126]

Great work... Loved it ❤️

[@ljg3794]

Simple but intuitive and powerful explanation! thank you!

[@Certbros]

That's really great to hear! Thanks for the comment. Glad you liked it.

[@sedikis.dolley3963]

Wow. Brilliantly explained

[@srinis9801]

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[@raamch]

Lot of useful and helpful information about port numbers. Thank you so much!

[@saltech2024]

OMG!!
Some tutorials are just too short but they explained everything you're looking for
Thank you very much

[@Certbros]

Thank you Ibrahim! Really great to hear you liked the video.
Good luck with everything.

[@89ulfr]

Best explanation I've heard on this topic...Thumbs up!

[@Certbros]

Thank you! Really glad to hear this 🙏

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I f'ing love CertBros!

[@578n.jhansisri5]

After a long time my doubt got cleared 😀😀

[@itaybarok9405]

Continue posting videos that this. You are a great teacher

[@shubhlaabh6342]

Thanks for making such videos man, 👍
It's helpful alot

[@shaahithahamadh4385]

Crystal Clear Explanation 👍 Thank You.

[@Certbros]

Glad you liked it

[@agyeirichmondowusu9670]

Your explanations and examples are the best

[@aruizsilva]

thanks for your work!

[@buzingaaaa]

Thanks for the explanation that's so helpful ❤️

[@denisewray4776]

Thank you, your video took the confusion out of understanding what Ports are and how they work.

[@Certbros]

Thanks Denise! Great to hear it helped.

[@bhaskarrao6083]

Excellent explanation!

[@98854arjun]

Wow finally now i understood why a port is required

[@mithun1247]

Thanks bro, your way of explaining these complex topics is the best. I learnt a lot from you. Thanks a lot. You earned a new subscriber

[@Certbros]

Thank you Mithun! Happy to help 👍 Welcome to the channel.

[@zenrobotninja]

Great explanation!

[@mattr7229]

Great explanation… thank you!!!

[@techanalogies2629]

Great Video. Understood so much in few minutes rather than searching on the web for hours

[@Certbros]

Great to hear it helped! Thank you.

[@sibusisosiyabongandaba698]

This is so clear, i liked and subscribed right away :-)

[@rohullahhussaini3351]

made it so simple, thanks

[@factswithai2]

great explanation, thanks for such good content

[@1juan1234]

Awesome video amigo , thank you 🙏🏼🙏🏼🙏🏼🙏🏼

[@micknimm-ne4ef]

you make it seem so much easier.

[@mofojackson]

Just saw your excellent video explaining TCP UDP and was going to ask if there was one on ports when this auto played haha. Awesome and exactly what I was wanting to know next

[@Certbros]

Great to hear! IP Addresses next 👍

[@user-kb4qc9od6t]

Thank you! Helped me so muc with my homework

[@kaidjohardudhiawala2549]

Superbly explained ,Thank you

[@raulsanchez4716]

Wow! This was an awesome video. Learned so much.

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Great Explanation !!

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amazing videos!!

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Great best one now I get it!

[@manaraljadani6309]

You made it much easier to understand. Thank you so much

[@Certbros]

Glad to hear it! 👌

[@chiromorilla7448]

Learning now for my CCNA cert

[@mohamedashik5374]

Thank you very much good explanation 💯

[@itsjankiinenglish271]

This is an excellent video!!! OMG it helped me A LOT!!! to understand Ports numbers!!

[@Certbros]

That's really great to hear! Glad you it helped you out 👍

[@justicekatlehopelesa8672]

Thank you so much this is helpful

[@tato2493528]

damn, what a clear explanation. ty

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Thank you sir. You have been great help 🆘

[@Certbros]

No problem at all. Glad to hear it!

[@usernotfound1044]

Thank you!

[@Certbros]

That's great to hear! Glad you got some value from this.

[@gajlaxmitrader]

You are simply awesome yaar
Wow.. i mean nobody explain like this simple way

[@VictoriaOtunsha]

Thank you for the simplification in the explanation.

[@Certbros]

No problem at all. Glad you liked it Ogiri 😀

[@bpd-ke6bs]

Thank you for making such great videos

[@Certbros]

No problem. Glad you like them!

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Awesome channel! Definitely thumb up!

[@Certbros]

Thank you!

[@nvlsvenu9336]

Thank You So Much!

[@Certbros]

You're welcome!

[@lynxoffinland]

a very helpful and informative video! Thankyou for educating me.

[@Certbros]

You're welcome. Glad it was helpful!

[@brokencranium]

Thanks! Great explanation!

[@Certbros]

Thanks! Appreciate the comment 👍

[@gardelrio9961]

Excellent explanation of ports.

[@Certbros]

Thanks Gardel!

[@JohnDoe-101]

Thanks!

[@04chavez]

Thanks for the video 🤠

[@Certbros]

No problem 👍 Glad you liked it!

[@jennymo2197]

fantastic content.

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[@L1vR-1948]

Thanks for this video :-) 👍

[@jesiotra6246]

thank you!

[@MKOladapo]

Well explained

[@randyallen8186]

Awesome! Thank you!

[@Certbros]

No problem!

[@Recordingization]

Perfect!

[@JaimeCB23]

Amazing videos and thanks for had shared with us

[@Certbros]

Thanks Jaime! No problem, glad you liked it.

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Hie thanks for a great review, im attempting to transition fro the construction industry into IT and i go introduced to the cisco skills for all program. I wasnt sure about its value but listening to this review has encouraged me a lot. My goal is cybersecurity and im not sure if i should leave the networking and focus on the security or i should run with both.

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THANK YOU SO MUCH!!!!

[@Certbros]

You're welcome!

[@bneutralnounprod.4948]

that was cool, thanks so much

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You're a life saver..

[@Certbros]

Your welcome 🙏

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Thanks for sharing

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[@Certbros]

Thank you!

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Nice video.Thanks

[@Certbros]

Thank you!

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OMG! That was extremely informative. The person explanation was on point. Even the most stupid Person in the world could understand that intel. Thank you kindly Mr 🙏🏻

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Super... I just tried netstat command got information in details .. Thanks you so much..

[@Certbros]

Great to hear! Glad you liked the video!

[@MariioThuqqen]

Love it

[@ajipratamahernanto2739]

Amazing.. thanks

[@Certbros]

Thank you Aji! 👍

[@zyghom]

"wrong": your house address is your IP, your name on the letter is your port because you can have many people living under this address.
Or, if instead of house if it is a block of flats: house number is an IP, room number is the port. But then we need also a "sub port number" for the names of people living in this room ;-)