how telnet works

hai Neo ,

good morning..

I would like to know the way how protocols work.

I read the RFC 854 and 318 , I was not able to intercept the way it works.

you can easily trace the way how protocols work using monitoring software, but for telnet it dosent work that way,

the result i got in packet capturing for telnet is

command will echo
command will suppress go ahead
command do terminal type
command do negotiate about window size

this dosent sense to me,,,,,,,,,,,,,,, so.....................

well ill tell you what i know which im afraid is very little as im not that advanced as of yet, but here goes;

all i know about telnet so far is that it is a TCP protocol and it is an old technology that is currently being phased out due to lack of encryption. most people only use it these days to access routers directly and its port is usually 23? im not positive about the port but pretty sure. im pretty sure it will be a circuit switched protocol as, as far as i know telnet establishes a connection before communication but i could be wrong.
anyways im just a step away from guessing now, like i said we havnt really touched on it yet.


about the response you received,
an echo as you might imagine is a remote node's response, your computer sends a frame, the node receives it and responds to the data which requests it be sent back. once it is sent, your computer would receive the new frame with the original data (new frame because the frame header and trailer would need to have been changed for the response). This basically just confirms communication.

now when it says WILL suppress go ahead i beleive its talking about telnet communication, meaning it is possible.

had to google this one, will do terminal type seems to mean that they are free to request terminal types... WILL and DO appear to be commands. perhaps something like AND, OR and IF in binary?

and the last one appears to be saying that its negotiating the window size, either timing window or application window im not sure.

looking at it overall from a new perspective it appears to be telling you what commands its using and then what its doing. eg. command (is) will (.) (requesting) echo
command (is) will (.) (performing) suppress go ahead
Etc

but thats just my 2 cents, i have absolutely no experience with telnet other than a few paragraphs ive read in the CCNA 1 course book.

i hope i helped somewhat, perhaps someone else can shed more light on it for you.

thanks Neo ,

You did a great job. I really appreciate you a lot.

Glad i could help