talking port to port

Discussion in 'other software & services' started by Pilgrim, Apr 26, 2003.

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  1. Pilgrim

    Pilgrim Guest

    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.
  2. Pieter_Arntz

    Pieter_Arntz Spyware Veteran

    Apr 27, 2002
    Hi Pilgrim,

    You mean something like this: ?


  3. Andreas1

    Andreas1 Security Expert

    Jan 29, 2003
    Mainz (Ger)
    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:
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