Linux中telnet客户端与服务端的安装与配置（yum安装）

Telnet服务的配置步骤如下:一、安装telnet软件包(通常要两个）。
　　1、 telnet-client (或 telnet)，这个软件包提供的是 telnet 客户端程序；
　　2、是 telnet-server 软件包，这个才是真正的 Telnet server 软件包！
　　安装之前先检测是否这些软件包已安装，方法如下：    [root@localhost ~]# rpm -q telnet    telnet-0.17-38.el5    telnet客户端一般默认情况是已安装    [root@localhost ~]# rpm -q telnet-server    无表示未安装二、安装telnet-client (或 telnet)
yum安装telnet-server，命令：yum -y install telnet，就能安装了。
三、安装telnet-serveryum方式是最为便捷的在线包安装工具。安装方式都可以直接搜索关键字，类似于：命令：yum telnet[root@crxjtest xinetd.d]# yum list |grep telnet
...
Trying other mirror.
telnet.x86_64 1:0.17-47.el6 @anaconda-RedHatEnterpriseLinux-201111171049.x86_64/6.2
telnet-server.x86_64 1:0.17-47.el6 local发现有telnet-server.x86_64这个源[root@crxjtest xinetd.d]# yum install telnet-server.x86_64
...
Trying other mirror.
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package telnet-server.x86_64 1:0.17-47.el6 will be installed
--> Processing Dependency: xinetd for package: 1:telnet-server-0.17-47.el6.x86_64
--> Running transaction check
---> Package xinetd.x86_64 2:2.3.14-33.el6 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

===============================================================================================================
Package Arch Version Repository Size
===============================================================================================================
Installing:
telnet-server x86_64 1:0.17-47.el6 local 37 k
Installing for dependencies:
xinetd x86_64 2:2.3.14-33.el6 local 120 k

Transaction Summary
===============================================================================================================
Install 2 Package(s)

Total download size: 157 k
Installed size: 312 k
Is this ok [y/N]: y
Downloading Packages:
Setting up and reading Presto delta metadata
Processing delta metadata
Package(s) data still to download: 157 k
---------------------------------------------------------------------------------------------------------------
Total 1.2 MB/s | 157 kB 00:00
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
Installing : 2:xinetd-2.3.14-33.el6.x86_64 1/2
Installing : 1:telnet-server-0.17-47.el6.x86_64 2/2
Installed products updated.

Installed:
telnet-server.x86_64 1:0.17-47.el6

Dependency Installed:
xinetd.x86_64 2:2.3.14-33.el6
Complete!
[root@crxjtest xinetd.d]#安装成功。可再搜索遍看是否已经写入环境中。[root@crxjtest xinetd.d]# rpm -qa | grep telnet
telnet-0.17-47.el6.x86_64
telnet-server-0.17-47.el6.x86_64发现telnet-server已经安装成功。 [更改配置文件，将telnet服务设置为默认启动，非必须]查询xinetd.d所管辖的所有配置文件所在目录。[root@crxjtest xinetd.d]# cd /etc/xinetd.d
[root@crxjtest xinetd.d]# ls
chargen-dgram cvs daytime-stream discard-stream echo-stream tcpmux-server time-dgram
chargen-stream daytime-dgram discard-dgram echo-dgram rsync telnet time-stream
[root@crxjtest xinetd.d]# vi telnet

# 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
}备份telnet文件，再vi打开，将disable值赋为no。修改完之后，:wq保存并退出开启telnet服务[root@crxjtest xinetd.d]# service xinetd restart
Stopping xinetd: [FAILED]
Starting xinetd: [ OK ]可直接start，这样就不会有关闭服务时候报的那个错，毕竟那个时候服务还不存在。测试telnet服务[root@crxjtest xinetd.d]# telnet localhost
Trying ::1...
Connected to localhost.
Escape character is '^]'.
Red Hat Enterprise Linux Server release 6.2 (Santiago)
Kernel 2.6.32-220.el6.x86_64 on an x86_64
login:测试正常。
参考文章：http://www.tuicool.com/articles/67be6fhttp://blog.csdn.net/frank_jb/article/details/40192349http://blog.163.com/wspjing@126/blog/static/117720534201272223820221/