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Author Topic: What EXACTLY are protocols? Does anyone really know?  (Read 5854 times)
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mmpal78
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« on: April 19, 2010, 11:01:06 PM »

What EXACTLY are protocols?  Does anyone really know?  I know the common answers:  "A set of rules and regulations to enable hardware/software to communicate over a network."  That answer is usually followed by examples like: "TCP, for example, transports info over the network and ensures integrity.  So if you loose a packet it will be recovered".

My question is what exactly is it?  For example:  How does TCP ensure that it gets there securely and what is TCP exactly?  Is it a program that if installed on both ends of the network know to look for such requests?  What language was it written in?  Is it open source? Can I write my own protocols? Whats the need for so many of them? If TCP can transmit info securely then why use FTP?  Why not send files via TCP?  Any recomended reading on this?
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ajohnson
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« Reply #1 on: April 19, 2010, 11:12:18 PM »

Most protocols are defined in RFCs (request for comments), but some are proprietary and closed. Google "TCP RFC" and you'll find several RFCs that cover various aspects of TCP.

You can write your own protocols in programming languages that support network programming if you want.

I think you mean TCP transmits information reliably, not securely.

You need to review the OSI and TCP/IP networking models. FTP is an application-layer protocol while TCP is a transport-layer protocol. FTP runs on top of TCP.

Check out Wikipedia and the RFCs for further reading. If you're looking for a textbook, grab a Network+ or CCENT book.

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« Last Edit: April 19, 2010, 11:13:53 PM by dynamik » Logged

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« Reply #2 on: April 20, 2010, 12:40:24 AM »

There are quite a few books available on networking and TCP/ IP, so just have a look at Amazon.
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Synquell
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« Reply #3 on: April 20, 2010, 02:43:05 AM »

I think this is the same question I asked myself a while ago :-)

As far as I can work out, what a protocol -exactly- is, is a text saying 'lets have it work like so, so and so'.

It's not programmed, it's not source code. It's an agreement of the form: when I send you those bits, you send me either those bits or those bits (or packets) back, within x seconds.

Every programmer can then make his own implementation of the protocol.
For example, when a company starts making a router, they look at the texts (RFC's) to see what is expected from them, what they need to send to other routers (router protocols), what they get from connected pc (DHCP requests for example), and they try their best to make it work out (some better then others).

If you would make a new car, you have to do the same: look at the rules and regulations to see how many lights you need, seatbelts, minimum specifications of brakes, etc. Those rules and regulations would be 'the protocol'.

This is all just 'as far as I know', me = newbie :-)
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« Reply #4 on: April 20, 2010, 03:28:03 AM »

I think this is the same question I asked myself a while ago :-)

As far as I can work out, what a protocol -exactly- is, is a text saying 'lets have it work like so, so and so'.

It's not programmed, it's not source code. It's an agreement of the form: when I send you those bits, you send me either those bits or those bits (or packets) back, within x seconds.

Every programmer can then make his own implementation of the protocol.
For example, when a company starts making a router, they look at the texts (RFC's) to see what is expected from them, what they need to send to other routers (router protocols), what they get from connected pc (DHCP requests for example), and they try their best to make it work out (some better then others).

If you would make a new car, you have to do the same: look at the rules and regulations to see how many lights you need, seatbelts, minimum specifications of brakes, etc. Those rules and regulations would be 'the protocol'.

This is all just 'as far as I know', me = newbie :-)

thats good enough to explain what protocols are  Wink think of agreements on authentication methods and ways to ensure that all the data gets to its destination. i couldnt have said it better...
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mmpal78
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« Reply #5 on: April 20, 2010, 09:11:52 AM »

Thank you all for your posts I really appreciate it.  Grin
These replys were way more helpful than any I got at school.
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Synquell
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« Reply #6 on: April 20, 2010, 10:00:39 AM »

School does have a way of being seriously useless at times Smiley
Cheers!
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« Reply #7 on: April 21, 2010, 02:34:28 AM »

speaking of school, have you ever been to this site? http://www.hackerhighschool.org/ it explains some basic things (come to think of it, probably also protocols) you might want to know about networking and other (offensive) security stuff. glad we could help!
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« Reply #8 on: April 21, 2010, 01:11:26 PM »

http://www.youtube.com/watch?v=x9XWxD6cJuY

'Nuff said.
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« Reply #9 on: April 22, 2010, 04:27:59 AM »

WOW, that brings back memories! i have seen that video about 7 years ago in class as an introduction for my bachelor. Corny, but great video!
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