安裝 ssh server

# apt-get install openssh-server

設定檔: /etc/ssh/sshd_config

重新啟動 ssh:

# service ssh restart

安裝 telnet server

# apt-get install xinetd telnetd

編輯 /etc/xinetd.conf，在 defaults 裡面加入成為:

defaults
{
# Please note that you need a log_type line to be able to use log_on_su$
# and log_on_failure. The default is the following :
# log_type = SYSLOG daemon info
	instances = 60
	log_type = SYSLOG authpriv
	log_on_success = HOST PID
	log_on_failure = HOST
	cps = 25 30
}

如果要修改 telnet 的連接埠 (預設是 23)，修改 /etc/services

telnet       23/tcp

還有更多設定……

編輯 /etc/xinetd.d/telnet，加上這幾行

# default: on
# description: The telnet server serves telnet sessions; it uses
# unencrypted username/password pairs for authentication.
service telnet
{
	disable = no
	flags = REUSE
	socket_type = stream
	wait = no
	user = root
	server = /usr/sbin/in.telnetd
	log_on_failure += USERID
}

甚至可以再加上這幾行

only_from = 192.168.0.100 #只允許192.168.0.100 IP 登入
only_from = 192.168.120.0/24 #限制只有 192.168.120.x 網段可以登入
only_from = .bob.com #只允許來自 bob.com 網域登入
no_access = 192.168.120.{101,105} #不允許這 2 個 IP 登入
access_times = 8:00-9:00 20:00-21:00 #只允許這 2 個時段登入
	......

重新啟動 telnet service:

# /etc/init.d/xinetd restart

或

# service xinetd restart

ref:
• 【Linux】在 Ubuntu 上安裝 SSH Server
• [Ubuntu] 安裝 Telnet server 及 SSH server

#linux #telnet