I have a server ( with red hat linux 9.0 ) and I need to telnet it. I tried
"Service telnet start" but it failed with a message "unknown service telnet". I looked into the file /etc/services..; telnet is there.

Is this problem due to squid service that is also running .Port that is used in squid is 3128, the default. but I would like to add that telnetting into port 25 (SMTP) was a suceess.

I tried nmap . and found that telnet port is open. But why doesnt telnet?
pls. help me.

that is because telnet is wrapped in xinetd. look in /etc/xinetd.d.

chkconfig telnet on ( or you may choose to edit the file yourself)
service xinetd restart


you are confusing two different thigs here - a telnet client and a telnet server (in.telnetd)

The above commands start in.telnetd. Also make sure you dont have any host based filters

Thanks for your quick reply. I want to clarify my problem bit more. When I meant telnetting into server..I mean telnet linux from a windows client. I also tried to telnet locally too (server-side). FAiled. So, I thought telnet service might be down. Bit of information that I missed in my previous question was that I tried /usr/sbin/setup and found: the server was at the highest level of security. I tried the configuration. Opened Telnet service from there, qutted the setup. Still the problem remained. I again opened "setup". And, "alo"!!
the configuration was at its default state, untampered. I dont know what is
the problem. I hope for your help.

The setup program only opens the port through the firewall. You will still have to enable the server in the way that linuxxed said.
Telnet is run through the so called superserver xinetd.
chkconfig xinetd on will modify configuration for xinetd.
service xinetd restart will restart and reload the new configuration.
When you try to telnet to your linux server then xinetd will fire up the telnet server.