hi all
i have two computers that are connected with LAN wire
one of them is running telnet server(IP=192.168.0.11)
other computer IP is 192.168.0.15
from other computer when i did {#telnet 192.168.0.11}
and type login name "root"
and its password it rejects the login

how we can login to a root account via telnet

What OS are you using?

First of all I would recommend you NOT use telnet, but use SSH instead, it does all the same things, but is more secure. Telnet should be considered deprecated and obsolete.

Secondly, why do you want to login directly as root? That's also a very insecure procedure as it could allow a brute force attack. You should instead log in as a regular user and then use "su" to switch to root, or better yet, "sudo" to execute any admin commands you need.

I suspect that you can't login through telnet as root because your distro has this disabled by default (which is very prudent).

There's really no need to login directly as root ever.

In general, you won't be able to login as root unless there's an appropriate console device listed in /etc/securetty and appropriate authentication config setup in /etc/pam.d/, but the specific details will depend on your distro.

However, I would again strongly recommend that you do not setup your system in this manner.

Install OpenSSH, login as a normal user and use "sudo" for any admin commands you need.

i want to know that is it possible well i am not going to use it this was only for my information.
i am using RED HAT ENTERPRISE LINUX 5.0 server edition(2.6.18-8)

Are these the only computers connected and are neither on the internet, and are you the only user? If all of these are true, then telnet would be OK. However you still should login as a regular user and use sudo for commands that need root access.
Unless you absolutely need a faster throughput, using ssh would be much better to use. Plus running a graphical program is easier to do. Simply use the "-X" argument as in "ssh -X user@host".

One thing that might be blocking you is /etc/securetty. Another is /etc/security/access.conf. The service could be disabled in the xinetd.d/telnet file. You really need read your logs to find out why access was denied.