First, I strongly recommend that you not run telnet on your machine. It is not secure, and sshd is readily available for Linux.
Is the IP address on your machine a private address or a routeable address? If it's private does some firewall or router external to your machine know how to forward to your machine?
Do you have a default gateway configured on your machine?
Are your daemons running? ______________________________________________________________________
TANSTAAFL!