talking port to port

[Pilgrim]

Could somebody help me??

i would like to know what kind of command and language are used when you connect directly to a remote port (telnet or any similar progs)...
It would be kind of you to precise any links where I could learn a bit more about that...

Thanx in advance.

[Pieter_Arntz]

Hi Pilgrim,

You mean something like this: http://simplythebest.net/info/telnet.html ?

Regards,

Pieter

[Andreas1]

Hi pilgrim,
obviously the commands available depend exclusively on the server program that is listening on the other end. after all, the client sends a request to the server and is then being served - if the request is supposed to be served, that is. The language of the requests varies a *big deal* between servers. E.g. a telnet servers accepts and handles completely different commands when compared with a MSMessenger server. However, there are two good news: most servers use a text-only (or mostly-text) language for their commands; and mostly we can infer on what server is running on the other end by the port we're connecting to and maybe even by a sort of "hello" message that it sends us when we're connecting to it. Wit both telnet and e.g. TDS's TCPconnect function, we can then emulate at least the text-only part of a communication and pretend we were a valid client for this communication.

Pieter has posted a link to a description of the telnet commands (and an actual telnet server is supposed to serve you a commandline on the remote machine).
I'd suggest you look after the "languages" of POP, SMTP, SSH, FTP, HTTP, IDENT servers for a start. When i get time, i will do a search for these myself but the first place to start with such a thing is always the RFC where these languages/"protocols" are defined: http://www.rfc-editor.org/cgi-bin/rfcsearch.pl