[Centos] Telnet 설치

Telnet 이란?

텔넷(TELNET)은 인터넷이나 로컬 영역 네트워크 연결에 쓰이는 네트워크 프로토콜이다

텔넷은 아래와 같은 특징을 가지고 있습니다. 

• TCP/IP 기반의 프로토콜
• 원격 터미널 접속서비스
• TCP 23번 포트 를 기본적으로 사용 한다. 

1.Telnet 설치 팩키지 확인 및 설치 

rpm -qa | grep telnet
yum install -y telnet*

• 설치 과정 확인

$ rpm -qa | grep telnet
$ rpm -qa | grep telnet*
$ yum list telnet*
  6ned plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
 * base: mirror.kakao.com
 * epel: ftp.riken.jp
 * extras: mirror.kakao.com
 * updates: mirror.kakao.com
Available Packages
telnet.x86_64                                             1:0.17-66.el7                                      updates
telnet-server.x86_64                                      1:0.17-66.el7                                      updates
$ yum install -y telnet*
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
 * base: mirror.kakao.com
 * epel: ftp.riken.jp
 * extras: mirror.kakao.com
 * updates: mirror.kakao.com
Resolving Dependencies
--> Running transaction check
---> Package telnet.x86_64 1:0.17-66.el7 will be installed
---> Package telnet-server.x86_64 1:0.17-66.el7 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

====================================================================================================================
 Package                       Arch                   Version                         Repository               Size
====================================================================================================================
Installing:
 telnet                        x86_64                 1:0.17-66.el7                   updates                  64 k
 telnet-server                 x86_64                 1:0.17-66.el7                   updates                  41 k

Transaction Summary
====================================================================================================================
Install  2 Packages

Total download size: 106 k
Installed size: 168 k
Downloading packages:
(1/2): telnet-server-0.17-66.el7.x86_64.rpm                                                  |  41 kB  00:00:00     
(2/2): telnet-0.17-66.el7.x86_64.rpm                                                         |  64 kB  00:00:00     
--------------------------------------------------------------------------------------------------------------------
Total                                                                               726 kB/s | 106 kB  00:00:00     
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  Installing : 1:telnet-0.17-66.el7.x86_64                                                                      1/2 
  Installing : 1:telnet-server-0.17-66.el7.x86_64                                                               2/2 
  Verifying  : 1:telnet-server-0.17-66.el7.x86_64                                                               1/2 
  Verifying  : 1:telnet-0.17-66.el7.x86_64                                                                      2/2 

Installed:
  telnet.x86_64 1:0.17-66.el7                           telnet-server.x86_64 1:0.17-66.el7                          

Complete!
$ telnet centos7
Trying 192.168.17.56...
telnet: connect to address 192.168.17.56: Connection refused

 

2.Telnet 접속 확인  

설치 텔넷 접속시 Connection refused 에러가 발생 합니다. 

텔넷 서비스가 중지되어 있어 접속 에러가 발생합니다. 

텔넷 서비스 활성화후 재 접속을 합니다. 

 

$ telnet centos7              
Trying 192.168.17.56...
telnet: connect to address 192.168.17.56: Connection refused

$ systemctl start telnet.socket 

 

$ telnet 192.168.17.56
Trying 192.168.17.56...
Connected to 192.168.17.56.
Escape character is '^]'.

Kernel 3.10.0-1160.el7.x86_64 on an x86_64
centos7 login: docker_test
Password: 
Last login: Thu Mar 31 15:54:04 on pts/9

 

3.Telnet Command

 아래 명령은 telnet 사용 기본 명령어 입니다. 

 

#telnet 서비스 시작
systemctl start telnet.socket

#시스템 시작 시 자동으로 telnet 서버가 시작될 수 있게 활성화 시킨다.
systemctl enable telnet.socket


#telnet 서비스 정지
systemctl stop telnet.socket
systemctl disable telnet.socket

#tlent 서비스 상태 확인 
systemctl status telnet.socket