Linux Telnet service installation and configuration

Because to upgrade ssh, in order to prevent SSH upgrade failed to connect to the server, install Telnet service for a rainy days, after upgrading ssh and then the Telnet service is Closed.

Telnet Server Configuration

first, Install the Telnet package (typically two).

　　

1, telnet-client (or telnet), This package is provided by the Telnet client program;

2, is the Telnet-server software package, This is the real Telnet server package!

Before installing, Check whether these packages are installed, as Follows:

[[email protected] ~] #rpm –qa |grep telnettelnet-server-0.17-38.e15

If the package is not detected and needs to be installed, the CentOS server mode has the Telnet package installed by default, but the server requires a telnet-server package.

[[email protected]/home/intone/packages] #rpm-ivh telnet-server-0.17-47.el6_3.1.x86_64.rpm

The Telnet Server package is installed on it, so let's take a look at it now.

[[email protected] ~] #rpm-qa |grep telnettelnet-0.17-47.el6_3.1.x86_64telnet-server-0.17-47.el6_3.1.x86_64

second, Start the Telnet service

　　

1. Open Service

Edit/etc/xinetd.d/telnet

[[email protected] root]# vi /etc/xinetd.d/telnet    # default:  on    # description: the telnet server serves telnet  sessions; it uses     #        Unencrypted username/password pairs for authentication.    service  telnet    {        flags            = REUSE         Socket_type     = stream        wait             = no         user            =  Root     &nbsP;  server          = /usr/sbin/in.telnetd         log_on_failure  += USERID         disable         = yes     }

Find disable = yes, change Yes to No and the service preset is off.

2. Activation Service

Telnet is hung under the xinetd, so it's natural to re-activate xinetd to re-read the settings in Xinetd.

[email protected] root]# Service xinetd restart

3. Set Telnet self-boot

[[email protected] root] #chkconfig telent on

third, Testing Services

By default, the system does not allow the root user to Telnet remotely. If you want to log in directly with the root user, you need to set the Following.

# echo ' pts/0 ' >>/etc/securetty# echo ' PTS/1 ' >>/etc/securetty

Restart the XINETD service to

[[email protected] root] #service xinetd Restart

Log in with normal user and root user respectively

[[email protected] root] #telnet IP

If configured correctly, you are prompted to enter the user name and password for the remote machine

Login:

Password:

If fire protection please be open, Modify firewall settings, open 23 Port Through. If the firewall is off, you do not have to do the Following.

Edit The/etc/sysconfig/iptables file and add the following line

-a input-m state--state new-m tcp-p tcp--dport 23-j ACCEPT.

Then restart the firewall

# Service Iptables Restart

Iv. Uninstall after using Telnet

1, edit/etc/xinetd.d/telnet, Find disable = no, change No to Yes.

2. Restart XINETD Service

[email protected] root]# Service xinetd restart

3. Uninstall the Telnet installation package

[[email protected] /home/intone/packages] #rpm  -e telnet-serverwarning: /etc/xinetd.d/ telnet saved as /etc/xinetd.d/telnet.rpmsave[[email protected] /home/intone/packages] #cat  /etc/xinetd.d/telnet.rpmsave # default: on# description: the telnet  server serves telnet sessions; it uses #        unencrypted username/password pairs for authentication.service telnet{         flags            = REUSE        socket_type      = stream                 wait            = no         user            = root         server          = /usr/ sbin/in.telnetd        log_on_failure  += userid         disable         =  Yes

This article from "7231238" blog, declined reprint!

Linux Telnet service installation and configuration