How do I enable telnet user access, meaning that I would allow telnet access only to particular username?
thank you
The answer is somewhat OS-specific. First, if you are *not* using Linux (or recent versions of Solaris), download the TCPwrappers library and read the manual. You will be able to do it by following this link:
Wietse's Home page
After installation, it would be wise (but not necessary!) to re-compile the telnet daemon from source, using the TCPwrapper library. Then configure the /etc/hosts.allow file to specifify that the telnet daemon will only allow user X from IP Y to log in.
I'm sorry I use Centos 4x tnx
Wow, you're really SOL. You should at least pay for free software. 
Do "man 5 hosts.allow"