How to open the Telnet service

In short, Telnet is a very important protocol. Of course, users will not study this thing. However, it is good for users who are exposed to Linux system to know more about it. So if you are using this system, take a look at this tutorial to learn about it.

First, check whether the rpm package of telnet-server is installed

OS:RedHat9

[root@locahost ~]#rpm -qa telnet-server

//For security reasons telnet-server.rpm is not installed by default, and the telnet client is standard. The following software is installed by default. For the convenience of testing, please confirm //

[root@locahost ~]#rpm -qa telnet

telnet-0.17-25

If it is not installed, please install telnet-server

The third disk has telnet-server-0.17-25.i386.rpm, enter the server directory to execute

[root@locahost ~]#rpm -ivh telnet-server*.i386.rpm

Second, restart the xinetd daemon

Since the telnet service is also guarded by xinetd, so after installing telnet-server, Start telnet service, you must restart xinetd

[root@locahost ~]#service xinetd restart

Third, test

Let's first check if TCP port 23 is enabled. Normal

[root@locahost ~]#netstat -tnl | Grep 23

tcp 0 0 0.0.0.0:23 0.0.0.0:* LISTEN

If the above line exists, the service is already running

Further confirmation by the machine

[root@locahost ~]# telnet localhost 23

Trying telnet 127.0.0.1…

Connected to localhost.localdomain (127.0.0.1) ..

Escape character is ‘^]’.

Red Hat Linux release 9 (Shrike)

Kernel 2.4.20-8 on an i686

login:

If the netstat command does not return content, we will have to proceed to a more in-depth configuration.

IV. Exclude possible problems

Modify telnet service configuration file

vi /etc/xinetd.d/telnet

service telnet

{

disable = yes

flags = REUSE

socket_type = stream

wait = no

user = root< Br>

server = /usr/sbin/in.telnetd

log_on_failure += USERID

}