Shulou(Shulou.com)06/02 Report--

Install telnet

Telnet is a standard remote login protocol with a long history. But telnet's conversation data is not encrypted, and even the user name and password are shown in clear text, which is a risky service. At present, most systems no longer install this service, and users need to install it manually.

1. Install telnet software, and users can install both the server and client of telnet.

[root@localhost wj] # rpm-qa | grep telnet

[root@localhost wj] # yum install-y telnet-server / / telnet server side, allowing other computers to connect

Installed:

Telnet-server.i686 1Rank 0.17-48.el6

Complete!

[root@localhost wj] # yum install-y telnet / / telnet client, which can connect to other computers

Installed:

Telnet.i686 1Rank 0.17-48.el6

Complete!

2. Configure telnet, modify the configuration file "/ etc/xinetd.d/telnet", and change the parameter disable to no.

[root@localhost wj] # gedit / 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

Server = / usr/sbin/in.telnetd

Log_on_failure + = USERID

Disable = no / / this defaults to yes. Only by changing it to no can you start telnet.

}

3. Modify the port. The default port of telnet is 23, and the user can modify the "/ etc/services" file to change the port.

[root@localhost wj] # gedit / etc/service

Telnet 23/tcp / / Port 23 is generally not used to prevent attacks. Note that port 23 here uses both tcp and udp protocols.

Telnet 23/udp

4. Modify the firewall to open port 23 of tcp and udp

[root@localhost wj] # gedit / etc/sysconfig/iptables

-An INPUT-m state-- state NEW-m tcp-p tcp-- dport 23-j ACCEPT

-An INPUT-m state-- state NEW-m udp-p udp-- dport 23-j ACCEPT

[root@localhost wj] # service iptables restart

Iptables: set chain to policy ACCEPT: filter nat [OK]

Iptables: clear firewall rules: [OK]

Iptables: uninstalling module: [OK]

Iptables: apply firewall rules: [OK]

Iptables: load additional modules: nf_conntrack_ftp [OK]

5. Start telnet

[root@localhost wj] # service xinetd restart / / telnet depends on xinetd

Stop xinetd: [OK]

Starting xinetd: [OK]

6. Test, connect telnet on the window side. Note that do not log in as a root user, which is not allowed by default.

[root@localhost wj] # telnet 192.168.0.119

Trying 192.168.0.119...

Connected to 192.168.0.119.

Escape character is'^]'.

CentOS release 6.5 (Final)

Kernel 2.6.32-431.el6.i686 on an i686

Login: david

Password:

Last login: Thu Aug 16 08:24:19 from 192.168.0.119

Already login

I have made a platform for Linux learning. At present, it comes out one by one, which you can refer to and use.

Link: https: / / pan.baidu.com/s/1GOLVU2CbpBNGtunztVpaCQ password: n7bk

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.