The telnet port probably isn't opening properly because you aren't completing the telnet negotiation sequence. I don't know whether you are familiar with this but it involves sending small cryptic binary messages to the server to negotiate with the client what options they both support. I wrote a C program to do this a while back - it just NAKed all the options the server sent it.

I discovered that some servers won't start up at all unless you perform the negotiation (Linux telnetd is one) whereas others are quite happy for you to charge in there ignoring the negotiation.

You could write the code for this, but as you've noted it is a bit of a pain. However you've got several other options.

TIMTOWDI of course!

In reply to Re: Telnet handshaking by ncw
in thread Telnet handshaking by rq-2102

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.