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

[@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!

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🤣🤣

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🤣🤣🤣🤣🤣 comment is so underrated

[@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

[@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

[@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

[@mrgigs08]

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

[@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

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You nailed it. A neat presentation.

[@tokinabo]

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

[@lilianapatarroyo6432]

Thank you! You explained so clearly.

[@Randumb96]

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

[@volcanoab4419]

Brilliant ... absolutely the best!!

[@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🤟🤟

[@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. 👍

[@thatguyluffy4941]

Crystal clear on the basics ! good explanation with the figures

[@Certbros]

Thank you!

[@moneymaker3400]

Best video for this concept in the whole KZbin.....love you guys❤️

[@shrutijain4126]

Great work... Loved it ❤️

[@mehdiroudeau8809]

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

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😊😊😊😊😊😊

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[@luckyplay9919]

This was so helpful!! Thank you

[@andrewdelave]

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

[@Certbros]

Thanks Andrew! Glad it was helpful 👍

[@ljg3794]

Simple but intuitive and powerful explanation! thank you!

[@Certbros]

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

[@raamch]

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

[@lawlietnao_music]

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

[@Certbros]

You're welcome! Thanks for the comment 👍

[@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.

[@shubhlaabh6342]

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

[@aruizsilva]

thanks for your work!

[@tanzeelazam9552]

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

[@Certbros]

Thanks Tanzeel! Great to hear you liked the video 👍

[@shaahithahamadh4385]

Crystal Clear Explanation 👍 Thank You.

[@Certbros]

Glad you liked it

[@user-ni4fs5pb3q]

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

[@sedikis.dolley3963]

Wow. Brilliantly explained

[@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.

[@agyeirichmondowusu9670]

Your explanations and examples are the best

[@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.

[@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 👍

[@mattr7229]

Great explanation… thank you!!!

[@buzingaaaa]

Thanks for the explanation that's so helpful ❤️

[@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!

[@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.

[@89ulfr]

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

[@Certbros]

Thank you! Really glad to hear this 🙏

[@1juan1234]

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

[@itaybarok9405]

Continue posting videos that this. You are a great teacher

[@raulsanchez4716]

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

[@factswithai2]

great explanation, thanks for such good content

[@bhaskarrao6083]

Excellent explanation!

[@mihailomarcetic2516]

Great Explanation !!

[@578n.jhansisri5]

After a long time my doubt got cleared 😀😀

[@user-kb4qc9od6t]

Thank you! Helped me so muc with my homework

[@zenrobotninja]

Great explanation!

[@cathydowns5442]

Einfach wunderbar erklärt! Danke...

[@sibusisosiyabongandaba698]

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

[@98854arjun]

Wow finally now i understood why a port is required

[@kaidjohardudhiawala2549]

Superbly explained ,Thank you

[@manaraljadani6309]

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

[@Certbros]

Glad to hear it! 👌

[@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.

[@VictoriaOtunsha]

Thank you for the simplification in the explanation.

[@Certbros]

No problem at all. Glad you liked it Ogiri 😀

[@vtsitsilaras]

amazing videos!!

[@micknimm-ne4ef]

you make it seem so much easier.

[@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 👍

[@johnconnor9787]

Awesome channel! Definitely thumb up!

[@Certbros]

Thank you!

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I f'ing love CertBros!

[@rohullahhussaini3351]

made it so simple, thanks

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Thank you for making such great videos

[@Certbros]

No problem. Glad you like them!

[@mohamedashik5374]

Thank you very much good explanation 💯

[@brokencranium]

Thanks! Great explanation!

[@Certbros]

Thanks! Appreciate the comment 👍

[@tato2493528]

damn, what a clear explanation. ty

[@KM-ew5rl]

Great best one now I get it!

[@krishnabugudi2512]

Thank you sir. You have been great help 🆘

[@Certbros]

No problem at all. Glad to hear it!

[@chiromorilla7448]

Learning now for my CCNA cert

[@justicekatlehopelesa8672]

Thank you so much this is helpful

[@trevorkubonga1140]

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[@usernotfound1044]

Thank you!

[@Certbros]

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

[@nvlsvenu9336]

Thank You So Much!

[@Certbros]

You're welcome!

[@randyallen8186]

Awesome! Thank you!

[@Certbros]

No problem!

[@gajlaxmitrader]

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

[@L1vR-1948]

Thanks for this video :-) 👍

[@lynxoffinland]

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

[@Certbros]

You're welcome. Glad it was helpful!

[@JaimeCB23]

Amazing videos and thanks for had shared with us

[@Certbros]

Thanks Jaime! No problem, glad you liked it.

[@04chavez]

Thanks for the video 🤠

[@Certbros]

No problem 👍 Glad you liked it!

[@drissalaouisoulimani7923]

THANK YOU SO MUCH!!!!

[@Certbros]

You're welcome!

[@jennymo2197]

fantastic content.

[@bneutralnounprod.4948]

that was cool, thanks so much

[@gardelrio9961]

Excellent explanation of ports.

[@Certbros]

Thanks Gardel!

[@ahilshaik8083]

awesome man ...keep going

[@Certbros]

Thank you!

[@JohnDoe-101]

Thanks!

[@itaybarok9405]

I understood the idea of giving a random port to the source because the port is used in the reply. Thanks. Also, I learned some new ports yet I would love to hear from you kore deeply about the 12 famus ports you showed because you did not go over all of them and you did not put enough information in each so I would like to hear more from it. However, wonderful video I learned from you in this video some important concepts and it sharped my knowledge.

[@Certbros]

Thanks for the feedback and I'm glad you liked the video.

[@msreddykotha5498]

very crisp and spot-on, love your videos. Could you please make a video on Virtualization.

[@Certbros]

Thanks! Great to hear you liked it. Yes, virtualization is on my to-do list 👍

[@MKOladapo]

Well explained

[@keerthanaa7740]

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

[@Certbros]

Great to hear! Glad you liked the video!

[@jesiotra6246]

thank you!

[@OmarzLiszt]

Thank you! helped a lot

[@Certbros]

Thanks Omar! Great to hear 👍

[@ETTopTech]

Thank you very much am from Ethiopia

[@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 ;-)

[@jeevansantosh686]

You're a life saver..

[@Certbros]

Your welcome 🙏

[@yassanhassanpour1442]

great explanation and motion graphic. tnx

[@Certbros]

Thank you Yassan!

[@frederickafrihyia6256]

Thanks for sharing

[@rahultist]

Nice video.Thanks

[@Certbros]

Thank you!