<![CDATA[静怡家园]]> http://www.zhanghaijun.com/index.php zh-cn http://www.zhanghaijun.com/post// <![CDATA[CentOS 6 7 上Telnet安装于配置]]> 碟舞飞扬 <webmaster@zhanghaijun.com> Sun, 10 Apr 2011 15:36:32 +0000 http://www.zhanghaijun.com/post//

yum install telnet telnet-server -y


安装之后修改/etc/xinetd.d/telnet文件，把disable那一行改为disable = no,[注：如果是CentOS7请忽略这一步]
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
        server          = /usr/sbin/in.telnetd
        log_on_failure  += USERID
        disable         = no
}


修改完之后，保存并退出

#CentOS上启动telnet服务并设置开机启动
service xinetd start
chkconfig telnet on
chkconfig xinetd on

#CentOS 7上：
systemctl start telnet.socket
systemctl enable telnet.socket

#CentOS默认防火墙没有开放23端口，所以我们要根据需要允许23端口
vi /etc/sysconfig/iptables
加入一条“-A INPUT -p tcp -m state --state NEW --dport 23 -j ACCEPT”

# Firewall configuration written by system-config-firewall
# Manual customization of this file is not recommended.
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -p tcp -m state --state NEW --dport 23 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT

保存并退出，然后重新启动iptables服务
service iptables restart

也可以输入以下命令：
iptables -I INPUT -m state --state NEW -m tcp -p tcp --dport 23 -j ACCEPT
立即生效，然后输入 service iptables save 保存当前防火墙规则。

#CentOS 7中防火墙配置：
firewall-cmd --permanent --add-port=23/tcp
firewall-cmd --reload
现在telnet服务已经可以使用了，下面我们来测试一下：
创建一个测试用户，并设置用户密码：
useradd telnettest
passwd telnettest

客户端配置，首先安装telnet客户端
yum install telnet
客户端安装完成之后，输入
telnet 199.99.99.189
输入上面创建的telnettest用户和密码登录

Trying 199.99.99.189...
Connected to 199.99.99.189.
Escape character is '^]'.

Kernel 3.10.0-123.13.2.el7.x86_64 on an x86_64
web2 login: telnettest
Password:
[telnettest@web2 ~]$


windows用户，安装了telnet客户端，同样也可以连接上服务器，当然很多其他telnet ssh软件也可以，如：SecureCRT、Putty等等
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