I've watched at least five or six videos in an effort to understand this concept and this is the first video that describes what the port actually IS! It's an opening in a firewall designated for certain types of traffic. THANK YOU DAVE!
I know very little about internet and I am a non-native speaker, but I am still able to fully understand what you said. You explained everything very clearly. Thank you very much!
Great video! Perhaps one detail mussed is that port 80 is the default HTTP port. HTTP is a protocol which can use any port number. There should be a service listening on that port in the server.
This is great, but how does a local OS firewall know what to allow back into the client? does the firewall open an outgoing port automatically in stateful manner and allows the local OS to listen on that port?
Hi! Awesome video! Thanks a lot. I would like to ask something: So you said port 80 is for http protocol and 110 is for POP protocol. So whey doesn't John uses those instead of 1000 and 1100 respectively?
Nice explanation. Do you have any videos regarding the TCP/IP and TLS protocols? Or source recommendation where I could read more about these topics? I have some basic knowledge of how they work but not quite sure if it's correct.
Thanks for the video. What limitations does the max number of allowed port numbers set for the system? Does it set max number of processes allowed to run at a time?
You've missed something here.. tell me the time in video where your question is.. The server does NOT allow a random request with a random port.. A server will allow incoming requests only from WELL KNOWN ports that it is configured to allow.. When it returns traffic to the sender, it will use a random port for its reply.
Dear Sir, I need some clarification regarding ports number used. why did u used 1000 for web and 1100 for email instead of their own 80/443 and 23 respectively. looking forward for clarification. thanks for being so informative.
There are source ports and destination ports in every 'message' that gets sent.. The SERVICES (like the web server) use port 80. The client that requests a web page uses its port address of 1000 (or some high port number). So the client sends an HTTP request with a DESTINATION port address of 80 .. this goes TO the web server. The SOURCE port address in that message is some high port number that can be relatively random as it comes from the client. All server services need to use port numbers that are known to everyone; so that everyone can send them messages. Clients don't need to use a public number, they just pick a high port number.
Hi! I understood the port concept! But I need a small clarification, when we open a web browser and an e-mail on our desktop, on what ports does the data move out, is it something like what I have read on different books, our desktop randomly chooses a port number from 1024 to 65535 and send the data out, but while coming back the data actually goes to the designated port? Is it like this? Or have I gone wrong somewhere? Please clarify.
you open a web browser.. you request a page using a packet. The packet sent out has a Destination port address of 80 because it is going to a web service.. the packet has a Source port address of.. say.. 48000. The firewall on the web server allows Destination port 80 traffic so the packet passes. The Destination port address of 80 routes the packet to the Web service. The web service sees this comes from port 48000 so the return traffic from the web server has a Source port address of 80 and a Destination port address of 48000.. The packet enters the client machine and the software see.. ahh.. this has a destination port address of 48000 and I know that the browser which is open has registered that port.. so I'm going to send the packet to the browser application
Learning Net+ now, came for insight. Just confused. -- Why is HTTP not port 80 in this example (Dave made it 1000)? Why is POP3 not 110 (Dave made it 1100)? I dont understand. I thought HTTP IS port 80 and POP3 IS port 110... that's it. Not randomly selected. How is the port selection actually determined? How does the packet/frame know that HTTP protocol or POP3 protocol is being used if the ports are not the default/standard 80/110?
This was answered in a previous post. The "well known" ports are from 1 to about 1000. These are 80 for HTTP and 110 for POP3 etc. These are the destination port numbers when clients sent TO a service. The SOURCE port number on the client is random and usually very high (above 40,000 or so). So the client sends a packets with destination port # 80 to a web server and it also lists the source port as #1000 (or higher). When the web server sends the return packet is uses this #1000 for the destination port number in the packet that is returned to the client. The client could have a number of browser windows open. The return port # identifies which window (process) the information should be returned to.
With a firewall, any unsolicited traffic is blocked. However, Port Forwarding allows some inbound unsolicited traffic. For instance: you can setup a rule so that anything inbound for port 60 will be directed to internal machine IP address of X. So any unsolicited packet received that has a destination of port 60 will be forwarded to Machine X which is in the internal network. This is the only way unsolicited traffic enters the internal network.
Thank you for the video. If a firewall generally allows outgoing traffic, will it allow spyware to send out info if the spyware was installed before the fire wall? does spyware create its own special ports?
yup.. that is why if you have a trojan on your computer. It makes an 'outgoing' connection to a hacker site and they can then find their way back into through the firewall to control your machine, because it is now 'solicited' traffic. (Basically, that is true.. some firewalls now attempt to look into the message further to see what is happening and potentially block it)
Sorry how is a protocol a service or an application? because you've mentioned that a port number is used to identify a service or an application, right?
a protocol is a set of rules that accomplishes some task. A protocol may use a certain port to complete its task as it communicates between two devices. The HTTP protocol defines the use of port 80 for Servers. So the Service part of the client-server pair uses the 'well-known' port address. There is a destination port address and a source port address in most IPv4 connections. A web server will use port 80. The client that requests an HTTP connection can use any random port above 1000.
How is it possible....two port connect in cpu one is dawn connectivity then, other one is automatically connect ......and how it's security is provided...
I've watched at least five or six videos in an effort to understand this concept and this is the first video that describes what the port actually IS! It's an opening in a firewall designated for certain types of traffic. THANK YOU DAVE!
10 years later, this video is still super useful, it's easy to understand the concept without any strugglings
I really appreciate it 🙏
Really good visual details and instructions. I really appreciated your teaching style!
Finally a good explanation. Thank you! Especially for the visuals, I've found I have a hard time understanding stuff if I cannot visualise it.
All these years poking around my various rigs and now that I'm studying for A+ 1001 this made some light bulbs activate. Thank you! 👍🏻
Finally someone explained it as a whole. Its so easy to understand but others make it more complicated than necessary.
I know very little about internet and I am a non-native speaker, but I am still able to fully understand what you said. You explained everything very clearly. Thank you very much!
Great video, thank you!
Fantastic Dave, very well done, very clear, very practical without getting too technical, and easy to understand, thanks from Suraj, Vadodara, India
this is perfect. your explanation, the way you present difficult concept in simple way. you are really a great teacher
Hey @Dave, This is the great explanation!! Thanks a lot!!👏
Just awesome. Many thanks!
Watched multiple videos. Only one accurate enough. Good Stuff man. Subscribed .
You made it simple. Thx a lot
I think you did a very solid job in this video! Thank you! It helped me understand how ports are used a lot better!
great stuff, clean and clear
finally a really clear and high quality video that makes things very clear for me. thanks
10 year old information and its still useful to this day
That is a very good ilustration of how TCP Ports and Firewalls work. Thx!
Thank you so much for that clear and concise explanation!
Highly informative. Awesome sir. Thank you❤🍻
Great Explanation. Thanks a lot Sir.
I know this is 9 years old, but you really saved my ass. Thank you.
Very understanding video. Thank you!
I appreciate the visuals, teacher at school only talks and its hard to imagine everything.
nice one. thanks. i found your explanation very helpful
Wow, you are a incredible teacher! Best regards
Very good explanation - many thanks
Brilliantly explained! I can use this in my computing lesson ...thank you!
Great video! Perhaps one detail mussed is that port 80 is the default HTTP port. HTTP is a protocol which can use any port number. There should be a service listening on that port in the server.
I really appreciated your teaching style! I hope to watch more.
Very useful , simple and good explanation . Thank you sir .
Thank you very much! This cleared up a lot of my questions that wasn’t explained well in the book I was reading.
That was a great explanation! Now I get why ports are listed as established or Listening.
Great explanation, thanks so much for this. The visuals and pacing were perfect
Thank you, this helped me get a better picture of the use of IP addresses and ports, hopefully it helps me write better backend code in the future 🙏🏽
Very well explained, i have always been intrigued as to how ports work and this was a very nice video, thanks for sharing.
this is brilliant, dave. well done! and thank you.
Wonderful explanation!
Great explanation!
Very clear explanation! hope u make more videos. Thanks!
Great tutorial and it helped me a lot. Thanks......................................
best explanation ty teacher diagram made me to understand the concept so good tyyy
Really great vid. Appreciated it!
Quality explanation. Kudos to you sir
Thank you for this beautiful explanation.
cristal clear , thank you so much Sir
This video is amazing! Thank you!
awesome and visible!
Nice video Dave. Have been looking for a video on Ports and IP Addressing and did not find any good ones.
Very well explained
This is great, but how does a local OS firewall know what to allow back into the client? does the firewall open an outgoing port automatically in stateful manner and allows the local OS to listen on that port?
Really good explanation, finally I understand what happens ;)
Thank you. Great explanation. I wish I could give you 2 thumbs up...
So good, so nicely explained...thank you...looking forward to more videos
Great! But what port Fred is using to send data back to John? Is it a random one?
Very helpful description - thank you.
Great useful video! The pictures helped in understanding.
very nicely explained!
amazing explanation! clear!
Awesome Explanation...very clear
ports are holes in firewalls...great explaination
Hi! Awesome video! Thanks a lot.
I would like to ask something:
So you said port 80 is for http protocol and 110 is for POP protocol. So whey doesn't John uses those instead of 1000 and 1100 respectively?
See a few comments above.. 80 & 110 are the "well known port numbers" and used by SERVICES (server), not by clients.
sir you nailed it
Thank you Nigel Mansell!
Many many thanks.
easy to follow and thorough explanation, thank you!
That was great bro, Thanks
Can you share more of your lectures ?
Thanks for that clear explanation.
Crystal clear man
you helped me so much
perfect!!!! thanks a million
Nice explanation. Do you have any videos regarding the TCP/IP and TLS protocols? Or source recommendation where I could read more about these topics? I have some basic knowledge of how they work but not quite sure if it's correct.
Look on my playlist "Networking". All stuff I have on TCP is there.
Thanks for the video. What limitations does the max number of allowed port numbers set for the system? Does it set max number of processes allowed to run at a time?
I'm not sure I understand the question. There are 65000 ports available. No limitations for the system.
ur video is helpfull so far !!
Great video, very clear...thanks!
very well explained.
Thank you. this really helped me out.
hey, i don't get it, why does the server's firewall allow a random request with a random port
You've missed something here.. tell me the time in video where your question is.. The server does NOT allow a random request with a random port.. A server will allow incoming requests only from WELL KNOWN ports that it is configured to allow.. When it returns traffic to the sender, it will use a random port for its reply.
High quality content
At 0:28, did you mean IP adress or Port number?
nicely explained!
Thanks mate, that was quite helpful..
Well explained.
Dear Sir,
I need some clarification regarding ports number used. why did u used 1000 for web and 1100 for email instead of their own 80/443 and 23 respectively. looking forward for clarification. thanks for being so informative.
There are source ports and destination ports in every 'message' that gets sent.. The SERVICES (like the web server) use port 80. The client that requests a web page uses its port address of 1000 (or some high port number). So the client sends an HTTP request with a DESTINATION port address of 80 .. this goes TO the web server. The SOURCE port address in that message is some high port number that can be relatively random as it comes from the client. All server services need to use port numbers that are known to everyone; so that everyone can send them messages. Clients don't need to use a public number, they just pick a high port number.
Great Explanation. Thanks
Thanks man
beautifully explained- thank you sir
Hi! I understood the port concept! But I need a small clarification, when we open a web browser and an e-mail on our desktop, on what ports does the data move out, is it something like what I have read on different books, our desktop randomly chooses a port number from 1024 to 65535 and send the data out, but while coming back the data actually goes to the designated port? Is it like this? Or have I gone wrong somewhere? Please clarify.
you open a web browser.. you request a page using a packet. The packet sent out has a Destination port address of 80 because it is going to a web service.. the packet has a Source port address of.. say.. 48000. The firewall on the web server allows Destination port 80 traffic so the packet passes. The Destination port address of 80 routes the packet to the Web service. The web service sees this comes from port 48000 so the return traffic from the web server has a Source port address of 80 and a Destination port address of 48000.. The packet enters the client machine and the software see.. ahh.. this has a destination port address of 48000 and I know that the browser which is open has registered that port.. so I'm going to send the packet to the browser application
Very helpful
yes it is. Are you a computer science student?
Learning Net+ now, came for insight. Just confused. -- Why is HTTP not port 80 in this example (Dave made it 1000)? Why is POP3 not 110 (Dave made it 1100)? I dont understand. I thought HTTP IS port 80 and POP3 IS port 110... that's it. Not randomly selected. How is the port selection actually determined? How does the packet/frame know that HTTP protocol or POP3 protocol is being used if the ports are not the default/standard 80/110?
This was answered in a previous post. The "well known" ports are from 1 to about 1000. These are 80 for HTTP and 110 for POP3 etc. These are the destination port numbers when clients sent TO a service. The SOURCE port number on the client is random and usually very high (above 40,000 or so). So the client sends a packets with destination port # 80 to a web server and it also lists the source port as #1000 (or higher). When the web server sends the return packet is uses this #1000 for the destination port number in the packet that is returned to the client. The client could have a number of browser windows open. The return port # identifies which window (process) the information should be returned to.
I understood solicited inbound traffic here. But can some one explain how port forwarding and unsolicited inbound traffic.
With a firewall, any unsolicited traffic is blocked. However, Port Forwarding allows some inbound unsolicited traffic. For instance: you can setup a rule so that anything inbound for port 60 will be directed to internal machine IP address of X. So any unsolicited packet received that has a destination of port 60 will be forwarded to Machine X which is in the internal network. This is the only way unsolicited traffic enters the internal network.
Thank you for the video. If a firewall generally allows outgoing traffic, will it allow spyware to send out info if the spyware was installed before the fire wall? does spyware create its own special ports?
yup.. that is why if you have a trojan on your computer. It makes an 'outgoing' connection to a hacker site and they can then find their way back into through the firewall to control your machine, because it is now 'solicited' traffic. (Basically, that is true.. some firewalls now attempt to look into the message further to see what is happening and potentially block it)
Thanks!
very helpful thanks
Thank You
Sorry how is a protocol a service or an application? because you've mentioned that a port number is used to identify a service or an application, right?
a protocol is a set of rules that accomplishes some task. A protocol may use a certain port to complete its task as it communicates between two devices. The HTTP protocol defines the use of port 80 for Servers. So the Service part of the client-server pair uses the 'well-known' port address. There is a destination port address and a source port address in most IPv4 connections. A web server will use port 80. The client that requests an HTTP connection can use any random port above 1000.
nice one!
How is it possible....two port connect in cpu one is dawn connectivity then, other one is automatically connect ......and how it's security is provided...
I don't understand that question.